Germinating, Planting, and Nurturing Torreya taxifolia
• Narrative Summary of Torreya's History and Growth Characteristics
PDF created by Connie Barlow in November 2020 for new torreya seed planters as
the most up-to-date (while short, 4 pages) summary presentation on this website
• WHERE to plant Torreya• How Far NORTH Will "Florida" Torreya Grow?• Orchard Style: Full Sun for rapid seed production (EXPERIENCED PLANTERS ONLY)
• Special Needs and Capacities of SUBCANOPY Torreya
• Beware of WATERLOGGING sites & soils (MUST READ!)
• STEEP SLOPES with a lot of upslope drainage area ideal
• Choose habitats based on INDICATOR SPECIES
• Summary Instructions for Volunteer Seed Planters
• DANGER OF "ROOTBOUND" POTTED SEEDLINGS
• GERMINATING from SEEDS (MUST READ!)
• EPIGENETIC ADAPTATION (for NORTHERN planters)
• BEWARE OF RODENTS (MUST READ!)
• ABILITY TO RECOVER from herbivory
How Far North Will "Florida" Torreya Grow?
ORANGE = entire "native range"
River systems for floating seeds southward
GLACIAL RELICT: As the glaciers receded, most plants were able to head north, although some are still lagging quite a bit in migrating as far north as the Holocene warming would enable. Torreya taxifolia, however, was "left behind" in its peak glacial refuge. It's very large seed precluded dispersal by wind. It could not float back upstream the river system it had been able to use for a fast float southward as the glaciers advanced. And apparently no far-ranging animal was interested in swallowing its seed for later defecation.
Fortunately, there are seed-producing, mature horticultural plantings in North Carolina.
The two oldest are both in the mountains of western North Carolina:
Biltmore Gardens, Asheville NC
Harbison House, Highlands NC
These and other historic northward groves of Florida torreya assure us that in the 20th century climate, the species was able to thrive at least 300 miles north of its historic range. As well, these northward plantings evidence none of the disease problems that have been devastating this species in its Florida range since the 1930s. Hence, Torreya Guardians (in contrast to the institutions managing seed distribution for the official endangered species recovery plan) generally distribute seeds northward of Georgia.
A. Naturalized Groves (with healthy offspring)
A1. Harbison House, Highlands NC
A2. Biltmore Gardens, Asheville NC
A3. Kennedy Home, Clinton NC
A4. Caroline Dormon Preserve, Saline LA
B. Mature Trees Producing Seeds
B1. Bullard Home, Mount Olive NC
B2. Callahan Home, Medford OR
B3. Bess Home, Cleveland OH
B4. Cheekwood Estate / Howe Garden, Nashville TN
C. Mature Trees Not Producing Seeds
C1. Henry Foundation, Gladwyne PA
C2. Spring Grove Cemetery, Cincinnati OH
C3. Chattahoochee River, Columbus GA
C4. Yinger Tree, York PA
C5. Kalmia Gardens, Hartsville SC
This conifer has been successfully producing seeds outdoors in western and central North Carolina for many years, so we know its habitable range is at least that far north. But how much farther north can it thrive? And how much farther will it be able to thrive 30 years from now, as climate shifts?
NORTHERNMOST TEST PLANTINGS OF TORREYA TAXIFOLIA:
• Parma OHIO (Fred Bess; PHOTO ABOVE, 2018)
• NEW HAMPSHIRE (Daein Ballard)
• Capac MICHIGAN (Paul Camire)
• central WISCONSIN (Mike Heim)
FIELD EXPERIMENTS IN NORTHERN STATES help us learn how far north this species can produce viable seeds later in this rapidly warming century.
PHOTO LEFT: Fred Bess beside one of his 5 Torreya taxifolia saplings at his home south of Cleveland, Ohio, October 2018. Fred shows how healthy the tree looks despite -17F degree winter temperatures in 2014.
Visit Fred's Torreya Ohio webpage for chronological reports, photos, and videos of his Torreya plantings.
Torreya seed production in Cleveland, Ohio:
2018 = 23 seeds
2021 = 168 seeds
• VIDEO: "Seeds of Florida Torreya Produced in Ohio".
Connie Barlow filmed this 2 October 2018 site visit. The VIDEO features important findings, including:
1. These trees have put forth leaves well acclimated to severe cold spells in Ohio. On the windward side of the tree, branch tips are occasionally killed, but a ring of new growth results and the tree becomes plusher and thus even more wind-proof.
2. Seeds are produced only on the branches that receive nearly full sun. (Connie notes from her 2005 site visit to wild California Torreya habitat that this seems to be a standard of the genus.)
Torreya Guardians 2015 addendum: In northern states it is best to locate trees where they are protected from winter winds. While many of our trees are planted beneath wild forest canopy (and some in ravines), others have been planted in areas exposed to winter winds. Northerly exposures are especially disastrous in northward states.
The most graphic examples of what happens to Florida Torreya when exposed to temperatures sub-zero F are in Ohio. The Dawes Arboretum 2015 video (near Columbus OH) begins with a beautiful torreya growing amidst dense shrubbery and beneath a giant white oak. That tree shows no damage from the brutal "polar vortex" the preceding winter.
In contrast, near the end of the video you will see a torreya located on a north-facing slope with a half-mile of unimpeded landscape northward; all but the terminal stem and bud suffered severe leaf-kill. In addition, our Cleveland OH torreya webpage posts photographs of terrible winter-wind kill of the evergreen leaves in the winter of 2013/14 (although the subsequent video shows full recovery 6 months later); that location is also unprotected by shrubbery or woodland surrounds.
Special Needs and Capacities of SUBCANOPY Torreya
The U.S. Fish & Wildlife Service in 1986 published the first recovery plan for the newly listed (as "endangered") Florida Torreya.
EXCERPT: "The Florida torreya is an understory tree of mature beech-magnolia-pine forests. The canopy trees are mostly deciduous, but evergreen hardwoods [Southern Magnolia] and conifers are also fairly common. These areas have diffuse sunlight in summer, and a relatively open canopy in winter
.... Other species of Torreya appear to have similar habitat requirements. Torreya californica is found 'on moist, shaded slopes and along water courses. [See the California Torreya webpage on this website.] Torreya nucifera is an understory element of beech forests in Japan. Torreya grandis occurs in mixed forests of southeastern China. Fossils of the genus occur in assemblages of other species indicative of mesophytic forests."
"... Under optimal conditions, growth continues after maturation, attaining heights of 60 feet. The largest existing tree is one that was moved to Norlina, North Carolina in 1840. It is 45 feet tall with a basal diameter of 34 inches." [Note: It was growing in full sunlight and later declined, being delisted as "national champion" of its species in 2016. But in 2021, Torreya Guardian Paul Camire made a site visit and found new vegetative growth on the tree.]
PHOTOS: Left was the Norlina NC Tree in 1975; growth form in full sun. Right is the largest of the 3 original plantings
at Caroline Dormon Nature Preserve in central Louisiana; growth form beneath a deciduous canopy.
Torreya's ADAPTIVE CAPACITIES for a SUBCANOPY lifestyle
The "CELIA" TREE: Slow-growing, but healthy
Waynesville, North Carolina
ABOVE: 2008 - The steep location chosen for planting the Celia Tree in July was extremely shaded by the lush deciduous canopy. Another photo taken November 2008, after leaf fall, shows the health and habitat of the tree.
LEFT: 2021 - Thirteen years later, again in November, the canopy leaves have fallen. Celia still looks very healthy but not much taller.
If, however, one of the canopy trees causing the most shade ever falls (and doesn't land on and crush the little torreya), the Celia Tree is likely to keep extending upward its central, leader, stem.
Torreya joins several other eastern USA trees that (unlike Torreya) can sometimes join the canopy, yet that have the unusual capacity to start-and-stop leader growth as canopy shading shifts. The three are American Beech, Red Maple, and Eastern Hemlock.
BELOW LEFT: The "HAZEL" was a potted seedling of the same size as the Celia tree when it was planted into a Lake Junaluska site in 2008. But, just 8 years later, in 2016 it was about six feet tall. Hazel was planted into a prepared full-sun site, and then the fast-growing surrounding plants began to shade it more and more under their canopy.
1. LARGE SEED. The large seed of Torreya is able to supply a newly emerging seedling with enough nutrients and stored energy to complete at least two above-ground growth spurts in very deep shade, while also growing roots.
ABOVE LEFT: The first growth-spurt is always a single upward stem, surrounded by radially emerging leaves.
ABOVE RIGHT: The second growth spurt is almost always a whorl of lateral branches (from two four) emerging from the stem tip. A second spurt of vertical leader growth can happen at the same time, or in a second growth spurt late in the growing season. Because the seedling in the above photo has the same light-green color on its branch pair and upper leader, we can surmise that they all emerged at the same time. The dark green lower leaves would have emerged the previous year.
A disadvantage is that the seed is also an extremely attractive food for rodents. 2. The evergreen leaves have a life-span (and capacity to photosynthesize) for up to about 7 years. When light is severely diminished, the seedling or sapling will go into the lowest scale maintenance mode producing little or no new growth.
3. Leaves are provisioned with habitat-responsive UV protection. The experience of Torreya Guardians is that sudden shifts from shade to sun will either "bronze" the leaves (which remain alive but then green up the following year) or will outright kill the leaves, but stored starches in the stem and root will produce a new flush of leaves with the proper amount of UV protection during the next growth season first at the branch tips and in subsequent years along the older section of the branches. LESSON: If you germinate your seeds in pots or protected beds, be careful to find ultimate destinations that do not shock them with UV amounts they are not prepared to handle.
long on-ground branches
BEWARE OF WATERLOGGING SITES AND SOILS
As of 2020, experience of Torreya Guardians indicates that this species does well in a wide range of sun and shade conditions. It is not a fast-grower, so under entirely natural conditions it would not be a pioneer species nor have a shot at any canopy. As with beech and hemlock and red maple, it can handle deciduous shade as a slow-growing understory tree for many decades, but also utilize a fortuitous canopy opening to become more lush and to head skyward. Well-established torreya have also been reported to handle drought well. THE ONE THING IT CANNOT HANDLE IS WATERLOGGING. Even the professional literature on this scarcely understood species regularly advises to plant on well-drained soils.
PHOTO ABOVE LEFT: In 2019 an arboretum in North Carolina not associated with Torreya Guardians sent us a set of photos for interpretation, as several of their T. taxifolia specimens showed yellowing/dying leaves. The full set of photos (and responses by various Torreya Guardians) can be viewed here. The arboretum staff person wrote, "I noticed a little yellowing last fall and it has gotten worse this spring. We have had record amounts of rain last year and this spring. GENERAL CONCLUSION, owing to the record rain plus the flat topography evident in this photo, is that the Torreya suffered waterlogging. And yet, it may recover. One month later, we received this report: ""I think our Torreya is having a new flush of growth on the branch tips. The largest one was hit the hardest and only has a flush of growth at the very top of the tree."
PHOTO ABOVE RIGHT: June 2020 we received this photo and request for interpretation. The information supplied was that the seedling was purchased from a nursery and planted the year before "at the end of a slight slope that stays wet after rain in NC, but often dries up as well in the summer. The lower branches are brown, so I'm not sure if that is heat stress or water stress?"
Our Torreya Guardian near Cleveland Ohio responded. Fred Bess wrote,"It is dead. May still be green but based on the apparent lack of turgidity in the needles, I'd say the roots rotted away. The black could indicate phytophthora but that would have to be tested for to be certain. I've lost seedling Torreyas to Phytophthora and those I lost look similar. If you replant Torreya, do not do so in the same spot as the disease is long lived in the soil and standard fungicides will do nothing. Also once a plant is infected there is no cure."
Fred Bess used raised beds for his level-ground planting in Cleveland,
from which seed production began in 2018!
FRED BESS continued: "Waterlogged soils are the most likely to house oomycetes like Phytophthora species. Once a plant is infected it cannot be cured. The few fungicides labelled for Phytophthora are used as preventatives only and even then may not do the job if the plants being protected are in wet soils. A friend lost his entire collection of plants to this disease. They were all bog plants and he used an ebb and flow system. Once the pathogen was in the water supply there was no hope for any of the plants within that system. I am exceedingly careful about my use of recirculating water and disinfect my rain barrels regularly."
FRED BESS concludes: "Torreya, in my opinion is very drought tolerant once established. Depending on the area of NC, a partly sunny well drained site would be best. Here in Cleveland they tolerate full sun all day and take the brunt of winter winds and even some road salt. The soil can also get pretty dry in summer. They do not seem to mind. Obviously there the sun shines hotter so a full sun location would probably not be ideal but well drained is key!
RECORD RAINFALL PROBLEMATIC: Another Torreya Guardian (in Tennessee) reported seedling losses owing to record rainfall. Court Lewis in Unicoi wrote:• JANUARY 27, 2019 - We've had an absolute monsoon here since last spring 10 months in which it has rained (or lately, snowed) nearly every day. 2018 broke all records for rainfall here and across the whole region, going up into the Mid-Atlantic. As a result, a number of the seedlings in cans have died. (Again, the bottoms of the cans are open, so that's not a factor.) When I pulled a couple out to look at them, the roots were rotted, along with the foliage. Note: Court had previously reported that, while he had added potting soil to the clay-rich local soil on his property, seedling growth may have been hindered/halted once the roots ventured out into the fully clay-rich native soil.
Connie Barlow visited Cox Arboretum in northwest Georgia in March 2019. This privately owned arboretum contained Torreya taxifolia, and two sister species from Asia: T. nucifera and T. grandis.
Here she studies the odd loss of inner leaves from a taxifolia, whilst the older nucifera planting directly behind her is lush. Is this an example of prior year waterlogging, followed by regrowth? Or is it the result of outplanting a very large potted plant from a somewhat shaded site to a full-sun site (which we know can cause UV injury, followed by regrowth the next year).
Overall, it is very helpful to share photos of torreya problems and outright failures (deaths), as well as photos of successes. We learn from both.
But what we can say for sure thus far is this:
Do not plant seeds or seedlings on sites where WATERLOGGING may occur! This means, avoid sites of CLAY SOIL or underlying CLAY HARDPANS. Avoid FLAT AREAS. Avoid sites that periodically FLOOD or that evidence plants that outcompete others in BOGGY or PERCHED SWAMP sites that can alternate between excessively wet and excessively dry (such as indicated by mosses and ground-level lichens). INDICATOR SPECIES OF TERRIBLE CONDITIONS: In the eastern states, RED MAPLE, SWAMP WHITE OAK, BLACK GUM as the canopy species likely indicate conditions very poor for Torreya, as do all boreal tree species in the northern states (WHITE CEDAR, LARCH).
STEEP SLOPES may be ideal
CONNIE BARLOW advises: My experience with wild California Torreya trees, especially those on the NW slope of Napa Valley, is that the species grows well on extremely steep slopes where north-facing ravines reach into higher elevations. As well, a 2020 paper on Chinese Torreya (T. grandis grafted onto other Chinese torreya rootstock for cultivation of highly valued food "nuts") advises:... Chinese Torreya trees usually grow in steeply sloping areas (e.g., with a slope of 65 degrees), even though surface water drains away rapidly in these areas due to gravity. They can grow in such an area because Chinese Torreya trees are drought tolerant. Some prominent Chinese Torreya trees even grow between rocks, because their roots can absorb water from the groundwater. However, based on field observations, it is known that drought could dry up young Chinese Torreya trees. In addition, Chinese Torreya trees cannot grow in areas that experience frequent flooding or soil water accumulation. A critical factor for the growth of Chinese Torreya trees is soil aeration; the space between soil particles can affect the respiration of the plant roots. Stones and rocks in the soil can significantly increase soil aeration....DON THOMAS, who lives in the southern coastal range of California Torreya, writes in 2022:... I live near San Jose, and I know that Torreya Guardians (Connie Barlow) have observed torreya growing in the hills above Los Gatos and in Swanton on the coast. I have been trying to visit nearby torreya stands to learn about their status. It grows naturally within 5 miles of my house in Montalvo County Park and in Stevens Creek County Park. In each place it is growing on a steep north-facing slope next to a creek, and there are only a few trees, with only a couple of seedlings present. As you probably know, California is in a severe drought, and conditions are becoming more marginal for the survival of the torreya.
Choose Habitats Based on "Indicator Species"
CONNIE BARLOW advises: Moist (but well drained) habitats with full or partial deciduous canopy shade may be ideal habitats for Florida Torreya in southern Appalachians and northward. As of 2019, Connie's suggestion for best "indicator species" is Christmas Fern, Polystichum acrostichoides. In addition to indicating ideal habitat, this tall and common fern may also camouflage Torreya seedlings during winter months and it attracts (and depends upon) the same form of "endo" (arbuscular) mycorrhizal soil fungi as Torreya evolved to partner with.
• CHRISTMAS FERN, Polystichum acrostichoides, not only occupies habitat in every state where Torreya Guardians have launched assisted migration experiments (MAP below left). This fern's habitat preferences (notably, rich soil, moist but well-drained, partial to full shade) are likely very similar to torreya's preferences. Here is how wikipedia characterizes this fern:Polystichum acrostichoides, commonly denominated Christmas fern, is a perennial, evergreen fern native to eastern North America, from Nova Scotia, Canada west to Minnesota and south to Florida and eastern Texas. It is one of the commonest ferns in eastern North America, being found in moist and shady habitats in woodlands, rocky slopes, and stream banks. The common name derives from the evergreen fronds which are often still green at Christmas in December.
PHOTO ABOVE RIGHT, January 2019: Connie Barlow examines a baby torreya four years after its seed was freeplanted in Shoal Sanctuary, west of Torreya State Park in northern Florida. See the fronds of Christmas ferns growing on opposite sides of the torreya. Yes, the fronds are excellent camouflage against deer herbivory, but because all nine seedlings at Shoal entirely escaped largescale herbivory whether they had any evergreen camouflage nearby or not this photograph is used instead to exemplify ideal placement of torreya seeds directly into soil alongside Christmas ferns.
Watch a 2019 VIDEO of a successful site of "freeplanting" four years after the seeds were planted; timecode 21:40 of Video 31b entails a pictorial explanation of why Christmas Fern may be an ideal indicator species. As well, "CONTRA-INDICATOR SPECIES", in Connie's experience include pioneer or dry-adapted common trees, such as Sassafras and Sourwood. Abundant pines indicate dry or wrong soil types (and you never want to plant torreyas under an evergreen conifer canopy; always deciduous!). Ericoid species harbor improper forms of mycorrhizae symbionts, and the evergreen subcanopy ericoids (notably, Rhododendron) will encroach upon the torreyas, blocking out crucial winter sunlight opportunities for photosynthesis. As well, floodplain species that withstand water-logging events, such as Red Maple, Silver Maple, cottonwoods, willows, and sycamores, must be avoided too.
• Learn the ecological indicators of your region's native trees: Great Lakes example
MIKE HEIM presented a 2-hour illustrated talk July 2020, which you can watch on youtube:
"Forest Trees of the Ceded Territory" (northern Wisconsin)
Torreya Guardians founder Connie Barlow reports,"Mike excels in offering solid guidance and images not only for identifying each species, but also its ecological context, historical uses, and deep-time history."Use this time-coded topical list for accessing specific tree species during this 2 hour lecture.
Connie Barlow continues: "Watching this video, I learned a vital ecological reason why Paul Camire has found in Michigan that RED MAPLE indicates poor habitat for planting Torreya. Instead, one would expect that native trees indicating well-drained rich soils (e.g., beech, sugar maple, basswood) would be good indicators of best potential Torreya habitats in the Great Lakes region."
It is very important for some Torreya Guardians to plant at least a portion of their seeds/seedlings in full sun. We call this "orchard style" because its purpose is to accelerate tree maturation and then maximize seed production. In the photos above you can see that orchard-style plantings require tending.
Photo above left shows how Russell Regnery (near Franklin, NC) protected his little trees with partial shading (for about 5 years). Exceptional droughts may also require supplemental watering, whereas seedlings planted beneath a forest canopy can easily withstand droughts in NC mountains after their first summer.
Photo right shows Jack Johnston using a weed-whacker around each of the seedlings he donated to the Tessentee Bottomland Preserve. Fast-growing weeds can deprive small seedlings of sun , but they can also partly block winter winds. Caveats: Important considerations in choosing orchard-style plantings are: (1) unshaded/unprotected plantings may be excessively vulnerable to leaf damage from summer drought and from bitter cold/dry winds in the winter; (2) very recent discoveries reveal the importance of healthy hub trees feeding sugars to young trees, so a field-style planting in full sun will lack that benefit; and (3) the point of orchard style is to speed up the rate of seed production, yet seeds will only be useful if they are not overly inbred so genotypic diversity in an orchard planting is crucial.
CAUTIONARY NOTE TO POTENTIAL PARTICIPANTS IN THE ASSISTED MIGRATION OF THIS ENDANGERED TREE:
Just in case genus Torreya is able to cross-pollinate between its distinct species that have been geographically isolated from one another in the wild for millions of years, please do not plant any Torreya taxifolia seeds or seedlings in proximity to either the California species (T. californica) or any of the Asian species (the latter of which are widely available in commercial nurseries). Please keep them miles apart. Genus Torreya is wind-pollinated. And even though this species is ostensibly dioecious (an individual produces either male or female reproductive structures), Torreya Guardians has photo-documented individual Torreya trees violating this rule. So caution is advised.
As well, if you own property west of the Mississippi, do not attempt to grow Florida Torreya there. We wish to keep America's eastern species of Torreya well isolated from wild stands of the native (and threatened) western species which may ultimately need to migrate northward into Oregon in future centuries. (There is paleoecological evidence of Torreya genus in Washington state.)
This cautionary note applies, as well, to any growers who would like to assist with the other conifer "left behind" in the Appalachicola peak-glacial refuge of the Florida panhandle: Florida yew (Taxus floridana). Do not plant this endangered tree near other yew species, if you wish its seed to be useful for conservation purposes.
PREVENTING "ROOTBOUND" PLANTS - It is widely known that leaving a plant (especially a taproot-capable plant like Torreya) in a pot too long can make them "rootbound". In such condition, the lateral roots have already started encircling the pot. If these roots are not shaken free and given the depth and width crucial for free-growth to resume, then the entire plant can end of "strangling" itself by its tight-winding roots. As it turns out, if the recipient soil around the dug hole where a potted seedling is planted is very dense, the roots, upon reaching it, may be inclined to initiate a new circle back upon themselves to stay within the soft zone hence, root-binding itself. In 2019 an article appeared that offers a way to prevent this from happening: "Why You Should Plant Trees in Square Holes". Whether planting a potted seedling or digging up an existing torreya for transplanting, never cut off the growing tip of the TAPROOT!
SUMMARY INSTRUCTIONS for volunteer seed planters (autumn 2020)
Because this webpage of propagation practices has grown huge over the past decade, Connie Barlow created this CHECKLIST November 2020 to assist new volunteer planters of Torreya seeds that we collected from two private properties in central North Carolina October 31.
✔ Keep the seeds somewhat MOIST in moss, peat, or soil but not damp or soggy.• A Narrative Summary of Torreya's History and Growth Characteristics in PDF was created by Connie Barlow in November 2020 to send to new torreya seed planters. It is 4 pages long, and the most up-to-date (while short) presentation on this website.
✔ Do not place in refrigerator, which could induce hibernation of embryo too early.
✔ IF PLANTING SEEDS INTO POTS, scroll down to the green box of detailed advice below.
✔ IF FREE-PLANTING SEEDS DIRECTLY INTO FOREST, keep reading this checklist.✔ Get seeds into the ground as soon as possible.
✔ Always plant seeds at least 4 INCHES DEEP (to deter squirrels)
✔ Plunge TABLE KNIFE all around your chosen microsite to ensure NO NEARBY VOLE TUNNELS. (Avoid sites near fallen trees or branches attractive to rodents).
✔ Use table knife (or trowel) for wedging open deep hole with minimal disturbance.
✔ INDICATORS OF GOOD MICROSITES: Deciduous canopy, climax tree species (e.g., Liriodendron and Beech in Appalachians; Sugar Maple and White Oak in northern test sites), adequate slope (to ensure no waterlogging), steep slope (to deter browsing if deer overpopulated), evergreen Christmas ferns (same mycorrhizal fungi and excellent winter camouflage), subcanopy and herbs that indicate rich forest soils not subject to drought: hydrangia, cohosh, trillium, deciduous magnolias.
✔ INDICATORS OF POOR MICROSITES: Evergreen (or no) canopy, evergreen shrubs (especially ericoids like rhododendrons, azaleas, and laurels); pioneer or weedy tree species; dry-adapted tree species (sassafras, sourwood); floodplain tree species (cottonwood, red maple, swamp white oak, basswood). Beware of planting on flat land, especially if there is a claypan. Beware of planting on south- or west-facing slopes in southern Appalachians except in the rainforest mountainous zone. Beware of planting on north-facing slopes subject to polar winds in the northern states.
✔ MAKE NOTE OF WHERE YOU PLANT. If you want to mark each site, consider using the flag / double-flag system pioneered by Chris Anderson in his Spring City, TN forested land. Over the course of just 2 days, Chris and his wife, Christina, free-planted 400 seeds November 2015, and then used a second flag over the next several years to mark spots where seedlings had emerged. The easiest approach, however, is simply to note and/or photograph general sites and marker trees or landscape features and record how many seeds are in each area. Then, delight in a kind of "Easter egg hunt" beginning one year later and intensifying into the growing season following the second winter (when most seeds will begin showing above ground). Watch this video of Connie Barlow and her husband sleuthing for seedlings on the site of Russ Regnery's forest near Franklin NC.
✔: BE PATIENT! Seeds will establish roots before they show above ground. Rodents or deer may sample early sprouting before you see it, but the seed will try a second time. So it may take as long as 3 or 4 summers for you to spot above-ground growth in every location.
✔: REPORT RESULTS ongoingly. Failures offer learnings just as important as successes especially if you can offer hypotheses as why your planting might have had weak results. Make sure you keep track of the emails/phones of Torreya Guardians supplying your seeds and in your local area. Report! And follow along on our group's events, learnings, and other items on significance by periodically checking our chronological Reports webpage.
GERMINATING Torreya taxifolia from SEED
BE PATIENT: highly variable germination time.
(Most seeds require 2 winters.)
SUMMARY ADVICE & BEST PRACTICES
TORREYA GUARDIANS experience through 2022 is that:1. Each batch of seeds will take several years to maximize germination success.BOTTOM LINE: Because seeds require adequate periods of Warm-Cold-Warm-Cold-Warm before germination will occur,
2. Extremes range from 6 months to 4 years, with a few seeds never germinating.
3. Too much moisture will cause seeds to rot; too little will kill by desiccation.
4. Freezing temperatures will kill the embryo.
5. "Winter" storage at temperatures above 42 degrees F are not cold enough.
6. Outdoor temperature fluctuations for seeds planted or stored at least 4 inches into the ground may be ideal.If you cannot ensure proper conditions of MOISTURE and TEMPERATURE over multiple years, then do consider FREE-PLANTING seeds soon after they have been harvested or after your first "winter stratification."
MORE SEED GERMINATION INFORMATION & ADVICE
• The 1986 recovery plan for Torreya taxifolia (its first) is highly recommended reading for all Torreya planters. The image below describes their best understanding of germination back in 1986. After that image, you will find a variety of recommendations drawn from actual experience by Torreya Guardians.
DETAILS ON SEED STRATIFICATION TEMPERATURES:In 2022 Connie Barlow read a number of technical research papers on SEED DORMANCY specific to close relatives of Torreya.
A very detailed paper on Cephalotaxus germination experiments indicated the absolute necessity of multi-week cold stratification at temperatures NO WARMER THAN 10 degrees C; ideal seems to be 5 degrees C.
Bottom line: If your refrigerator is not below 50 degrees F (41 degrees may be ideal), then your stratification method may be inadequate.
LEFT A: May 23, 2015 - In May, Connie was distributing to volunteer planters in various states seeds from the prolific autumn 2014 seed harvest. While many were cracked at one tip (evidence of pending germination), only two had radicles extended at this time. Connie chose to plant each along the side of a large clear glass jar, in order to watch growth throughout the summer.
LEFT B: June 29, 2015 - A month later, one of the two seeds had grown just a little, while the other was visible several inches above the soil layer. Two additional cracked seeds buried in the jar showed no additional signs of growth.
Advice from 1998 paper "Ex Situ Conservation of Stinking Cedar"Germination of Torreya seed, like many primitive gymnosperms such as Taxus and Podocarpus, can involve a long after-ripening of the embryo once the fruit senesces from the tree. If seed were used it would have to be preconditioned and planted at the cusp of germination, thus avoiding a long period of dormancy in the ground when it would be subject to predation.
FRED BESS February 2016: "I have gotten almost 100% germination on 150 seeds from the 2014 crop. As of now there are only 13 seeds that have not sprouted. It would seem they germinate better after double stratification [2 winters]....
Photo by Fred Bess, February 2016
(Torreya Guardian near Cleveland, OH)
"When they arrived I put them into a 1-gallon ziplock bag with about 4 cups of slightly damp peat/soil mixture and placed it under the bench in my greenhouse (temperature rarely dips below freezing there).
"I checked the bag beginning Spring 2015 weekly and removed any that germinated, then resealed the bag and placed it back under the bench.
I hadn't looked at the bag since about Thanksgiving 2015. To my surprise, today (February 6, 2016) I found that all but 13 of the rest of the seeds have germinated. Most are just showing the radicle; a few have sprouted significantly."
Additional note from Fred: "The zip bag was not open but sealed at all times except when I was inspecting for germination. Since I opened the bag regularly to check germination, that would let plenty of fresh oxygen into the bag and I never tried to squeeze air out before resealing. Because the bag was sealed I never had to add moisture and the peat was only barely damp (to ensure the seeds would not rot). The seed bag was stored on a shelf under the benches of the greenhouse; in my opinion, they received as much light as they probably would if a squirrel had buried them or if they were covered with leaves. Being in the greenhouse they also experienced the heat of summer and the cold of winter; I heat the greenhouse only to about 40-45F. The greenhouse has dipped below freezing two or three times when the heating system failed. Without a greenhouse, I would store the seeds in the refrigerator for the winter and remove them for spring, summer, and fall so that they experience the seasons. This appears to be quite important since the great majority of the seeds germinated after the second stratification."
VISUALLY DETECTING SIGNS OF PRE-GERMINATION
(photos by Connie Barlow)
ABOVE AND BELOW: May 2022 after the first WINTER STRATIFICATION. Notice that germination begins with a crack at the pointy tip of the seed. The photo below right has not yet developed a slit, but notice that it retains a shiny portion of the clear, papery covering that reveals the light, smooth color surrounding the tip nearing germination time.
GERMINATION IS RARE AFTER ONLY ONE WINTER: The photos here were taken from a batch of torreya seeds harvested November 2021 and overwintered by Connie Barlow in soil in the same insulated container (a small cooler) usually on the porch in southern Michigan, but moved into the unheated entryway when temperatures dipped well below zero F at night. Of the total 85 seeds, only one germinated by early May 2022.50 - no slitOBSERVATION CONTINUES: Connie has put all 85 seeds in loose potting soil, in containers distinguished by category (primarily slit v. no slit) so that every few weeks she can check for changes. She hypothesizes that the lone germinated seed will grow a root immediately but not grow an upward stem until late summer. Some of the slitted seeds may continue into radicle emergence, but likely few will show any above-ground growth this first summer. A few of the no-slit seeds may develop slits and then a radicle will emerge late in the summer and develop the main taproot (but no above-ground growth), but most will not develop slits until Spring of 2023 (which, in our experience usually is the maximal germination time). And then, keeping the experiment going, it is possible that as many as 15 or 20 seeds will show no germinated radicle until after the third winter stratification. It will be interesting to see if any seed develops a slit in late summer or fall that carries through a winter without first developing a root. Is it safe for a seed to carry through the winter with a slit, but not a fully developed root?
32 - slit
01 - germination (top row L)
01 - very large crack (top row R; probably harvested that way) with no radicle emerged
01 - outer covering mottled with soft patches; gray color (dead)
ABOVE: Horizontal view of 3 uncracked (L) and 3 cracked (R), with tips facing camera.
BELOW: Top view of same row of seeds. Notice the DARK SPOT near the tip of each seed. Flipping over the seeds reveals a dark spot on the bottom side, too. The spots are actually darkness indented easily seen in the two close-ups of seeds directly above. These dark indentations do not usually appear in freshly harvested seeds with their fleshy covering removed.
REMAINING QUESTIONS: (1) When and why do the dark indentations develop? Might they be a thinning where moisture can penetrate the seed coat, thus helping the radicle push through the tip? (2) At this stage the seeds will always settle with the two dark spots nearly at top and at bottom, and the initial slit always develops vertically as if reaching for both spots. When and why does this weight differential develop?
ABOVE: Seeds are ripe only when their fleshy sarcotestas easily pull away. (This happens in late September or early October, but it is believed safest to harvest the seeds when they turn orange and purple in late October to early November.) Notice that the fresh seeds do have a point, but not as much as after winter stratification, as the embryo develops. And notice that the seeds also lack a dark indentation near the point.
LEFT: Seeds cut in half. The green-flesh seed easily sliced in half with a serrated kitchen knife. The purplish seed was harvested a month later, so it is riper and it required 10 minutes of "sawing" using the same knife in order to make the same cut.
QUESTION: Does this difference in seed coat hardness indicate that early harvested seeds are more susceptible to being killed by drying out?
Photos were taken by Connie Barlow, November 2013, and the operation she conducted can be seen at timecode 01:03:55 of her 2013 video on youtube: "Helping Plants Move North in Anthropocene Climate: Torreya Guardians 2013 Report".
ABOVE: Notice that when the seed is "ripe" the embryo is either tiny or nonexistent. Especially the most ancient (Jurassic or early Cretaceous) families of plants that managed to avoid extinction tend to have a dormancy style known as Morphophysiological Dormancy (MPD). Tree families include Annonaceae and Magnoliaceae among the angiosperms, and Ginkgoaceae and Taxaceae among the conifers. Torreya is a genus in Taxaceae.
The MPD dormancy type means this:Seeds readily imbibe water but have embryos that are underdeveloped and/or undifferentiated and physiologically dormant.
To learn more about this DORMANCY type and why winter stratification is crucial (as well as the adaptive value of germination occurring over multiple years) consult: "Dormancy and germination: making every seed count in restoration", 2020, by Olga A. Kildisheva et al., Restoration Ecology... or ...
VIEW EXCERPTS OF THIS PAPER AND OTHERS ON DORMANCY / GERMINATION
WARNING! KEEP SEEDS IN THE DARK: If you overwinter seeds in your fridge, wrap their bag in a towel to ensure NO LIGHT GETS IN. Experts say that seeds require darkness to germinate (else they think they are on top of the ground, with inadequate soil or leaf cover, so they would be in danger of drying out if they germinated).
WARNING! 2021 UPDATE: TORREYA PLANTERS IN NORTHERN STATES PLANT FOR EPIGENETIC ADAPTATION! This ancient tree genus has enormous capacities to epigenetically adapt to your climate conditions IF you put the long-to-mature seed directly into your outdoor ground before the rootlike radicle emerges. Go to the EPIGENETIC SECTION of this "propagate" page and review the new information before you continue reading here.
WARNING! PLANT SEEDS BEFORE OR VERY SOON AFTER RADICLE APPEARS: Genus Torreya (and some other forest tree species) associate with arbuscular mycorrhizal fungi. This is an ancient plant-root-fungus association in which the plant can develop roots BUT NOT ROOT HAIRS if unaided by fungal partners. Perhaps the "brittleness" problem obtains from this developmental hurdle. BOTTOM LINE: When FREE-PLANTING SEEDS directly into forest habitats, note whether there are plant species nearby that can be expected to have already partnered with arbuscular (endomycorrhizal) fungi. Access this section and LIST OF PLANT SPECIES THAT ALSO PARTNER WITH ARBUSCULAR MYCORRHIZAE.Additional note from Fred Bess: The radicles are very strong and don't seem particularly brittle. However, once the top growth begins, the connection between the developing seedling and the seed itself does seem much more fragile. I always take care when inspecting seeds.
WARNING! NEVER LET THE SEEDS DRY OUT OR FREEZE Case Study 4 (p. 23) in an online pdf, published 2014 by Botanic Gardens Conservation International, summarizes the work of the Atlanta Botanical Garden in biodiversity conservation of Florida Torreya. The report is Global Survey of Ex Situ Conifer Collections. The Florida Torreya Case Study (p. 23) was written by Jennifer Cruse-Sanders of the Atlanta Botanical Garden.EXCERPT: "One of the limiting factors to ex situ conservation of this species is the inability to use conventional seed storage techniques for preserving germplasm. Torreya taxifolia produces recalcitrant wet seeds that cannot be dried for storage in freezers. Therefore, until recently the only way to maintain ex situ germplasm was through living collections. In collaboration with Georgia Institute of Technology, a somatic embryogenesis tissue culture system was developed to initiate cultures, produce somatic seedlings and cryogenically store cultures of T. taxifolia. Large numbers of somatic embryos and resulting seedlings can be developed in culture from a single seed. One of the lessons learned was that the water potential (-MPa) of T. taxifolia gametophyte tissue rises greatly, in contrast to many other coniferous tree seeds, during seed after-ripening, and mimicry of this rise in vitro is necessary to continue development of somatic embryos to produce new seedlings in culture. All of the genotypes tested for cryopreservation were successfully recovered after retrieval from liquid nitrogen and can provide material for disease research, restoration or establishment of seed nurseries for conservation."TORREYA SEEDS CANNOT BE STORED. Torreya's seed is recalcitrant and cannot be stored except via cryo-preservation following laboratory manipulation of tissue culture via "somatic embryogenesis". The thousands of seeds currently being produced ex situ must therefore be used for plantings or will be lost. They cannot be inexpensively stored. In 2018, a paper published in Nature Plants confirmed that a large proportion of plants (especially endangered plants and notably trees) have recalcitrant seeds that cannot be stored: "Seed banking not an option for many threatened plants".
• ADVICE FROM LEE BARNES (2010) Several folks have commented on the need to not let seeds dry out prior to cleaning and stratification. I am concerned that seeds that "float" may have lower germination due to drying or less stored food, etc. but Dr. Croom noted that he had heard of good germination of "floater" seeds (pers. comm. with Maclay Gardens in Tallahasse, FL. who indicated 80% germination from floaters). Others suggested soaking seeds for 24 hrs. after cleaning off flesh. I retested my initial "floaters" that had been stored for several weeks in moist sphagnum moss and found that most were now "sinkers." I did have one uncleaned seed that had rolled behind a container and dried for two weeks that audibly rattled inside the woody seed coat; I tried re-soaking the seed but it remained a floater even after everal days of soaking. This suggests that as little as two weeks drying can damage a seed, so I suggest that all seeds be stored in moist sphagnum immediately upon collection and prior to removing fleshy tissues by cleaning. I am curious if the floater seeds might have aided distribution of a species [by river transport] now primarily found growing along a major river? Editor's note: The Chattahoochee River flows from the southern Appalachians all the way to the Gulf via the Apalachicola River, the native range (glacial refuge) of Torreya.
Seed SCARIFICATION (scarring): Does it hasten germination?
Lamar Marshall mechanically scarred all his seeds from the 2013 harvest with a hacksaw (Connie Barlow used a serrated kitchen knife). None of Lamar's germinated in 2014, but 50% germinated in the spring of 2015 and many of the remaining germinated that summer or fall. (Use pliers to ensure the blade doesn't slip down the seed onto your fingers.) It is really easy to sense when the blade has cut through the thin shell; stop before it defiles the seed flesh beneath.
Daein Ballard also received seeds from the 2013 harvest; he did not scarify any, yet had similar success. So we need an actual experiment. Someone needs to scarify half their seeds, and report results. Scarified seeds will dry out and die if not planted immediately. Learn more about botanical scarification.
ABOVE: April 2012 Connie Barlow did a test planting of 4 seeds that she had kept refrigerated from the 2011 fall harvest. Two she scarified and two she left untouched. All four were moistened and then immediately planted in moist soil. Unfortunately, in 2012, we still hadn't learned to plant seeds at least 4 inches deep. So rodents got them all; the experiment was quashed.
2011 Advice from Jack Johnston (northern Georgia):
• See the 2010 site visit captioned photos of Jack Johnston's methods of germinating, rooting and outplanting Torreya taxifolia.
GERMINATING IN POTS: "Two years ago I had seeds and planted them outside in Dec. in one gallon pots with many slits down the sides. Drainage was good. Germination occurred the first and second spring. I have found that using pots is easier than dealing with voles that get in seed beds. Germination was excellent using pots. After seedlings were a few inches high, they were moved into individual pots."
GERMINATING IN GROUND: "In-ground protection is fine for planting. The chestnut folks use a tin can with both ends cut open to shove the can into the ground below the usual vole level. It works fine. Then they take hardware cloth and make a circle around the planting and pinch the top together until growth is well underway. The little wire cages are about a foot tall or less. 1/2 inch hardware cloth keeps voles and rabbits away." Note: Jack cautions, "Once I planted 100 chestnuts in the middle of my yard in the ground and had squirrels come from the woods and eat every one of them. I think planting Torreya seeds will be a waste of seeds if a squirrel can get to them. I even remove the used-up seed before planting seedlings."
Torreya seedlings (2007 seed harvest) sprouting at home of Jack Johnston in NE Georgia in summer 2008.
2012 Advice from Lee Barnes (western North Carolina):
Experience has now confirmed that, even though some harvested seeds are "floaters" (they float in water), they actually can germinate. So do not give up on them. (It usually takes about 18 months for any seed to germinate, and sometimes a year or two longer.)
CAUTION: Never let Torreya seeds dry out before you plant them; but do not water-log them either. We mail them in a plastic bag with peat or sphagnum. If you receive seeds and overwinter them in the fridge before planting, you can mix good soil into the container. (Keep the bag slightly open to ensure oxygen exchange.)
In 2014, Lee made sure that the 300 seeds he was responsible for had a natural experience of winter cold ("cold stratification") before he distributed them in the spring. He put holes in the bottom of a plastic bucket, put the seeds + soil into the bucket, buried the bucket so its rim was at ground level, and put wire mesh (rodent protection) across the top.
2017 Advice from Clint Bancroft: DON'T GIVE UP ON THE FLOATER SEEDS!
Editor's note: Jack gave Clint 150 seeds from the 2015 fall harvest, 91 of which were floaters (which Clint planted separately in order to keep track of any differences in success between floaters and sinkers).
RESULTS (reported May 2017): "These were seeds from Blairsville given me by Jack Johnston in 2015. I did not record exact counts, but as expected, there was a significant difference in germination between floaters and sinkers. The first germination came only 7 months after planting outdoors. That was a pleasant surprise and the floaters germinated in significantly higher numbers than the sinkers. Interesting! Counterintuitive! Bottom line: Don't give up on your floater seeds." 5 January 2021: "I HAVE noticed a difference in germination of sinkers vs floaters. The floaters had a higher germination percentage. This information is on my page somewhere. I forget the source of that seed lot. I have some seeds (probably Highlands or Clinton) segregated into floaters and sinkers that should sprout this year. I will report on results."
2014 Advice from Connie Barlow:
I visited Torreya State Park in northern Florida in December and talked with a park warden while observing together the Torreya plantings at the main parking area. He told me that local folk have found that seeds sometimes take 3 years to germinate. I now speculate that perhaps Torreya genus has survived since its origin in the Jurassic in part because it does not 'put all its eggs in one basket'. Variable (including extremely delayed) germination may have helped this genus survive supervolcano and meteor-impact events that eliminate growing seasons for perhaps three to six years.
2015 Advice from Connie Barlow: BEWARE OF FUNGUS!
Torreya seeds must never dry out, so how does one store them through the winter? Stratifying torreya seeds outdoors in real soil (protected from rodents) or by "free-planting" seeds individually into their permanent forest plots is always the best approach. But for those of us who need to store hundreds of seeds over winter while we seek volunteer planters, we often resort to peat moss (sphagnum) in a protected container (outdoors, or in fridge or garage) periodically moistened to keep the seeds from drying out. Fred Bess has had success with this method, as have I, but if I wait too long to get the seeds distributed (and especially if I remove them from the refrigerator), those that begin to crack for early germination become vulnerable to fungal infection.
PHOTO ABOVE: If you see any white at the tip of a cracked seed, and if that white is not firm (like a root) but is liquid or pasty, then your seed is rotten. Give any cracked seed a squeeze and see if any of that goop oozes out of it. Yuck!
DAMP NOT WET: If you stratify/overwinter seeds in a plastic bag, use damp, not wet, peat moss filler.Experts say that seeds require darkness to germinate (else they think they are on top of the ground, with inadequate soil or leaf cover, so they would be in danger of drying out if they germinated). NO LIGHT: If you overwinter seeds in your fridge, wrap their bag in a towel to ensure NO LIGHT GETS IN.
PHOTOS BELOW: Jim Thomson, Torreya Guardian in Cullowhee NC, ensures that multiple seeds germinated in the same pot do not entangle roots.
Jim Thomson uses foam-board dividers to segregate a single pot into halves.
Notice, as well, that the apex stem of the specimen on the right had had its tip nibbled off by an animal yet the following spring it had already sent up a new vertical stem from partway down the old stem. Notice the light green color of that new vertical stem growth.
If you overwinter your seeds in pots outdoors, bury the pots to the surface of the surrounding soil (photo above) to modulate heat and cold penetration appropriately.
2017 Advice from Paul Capiello, executive director of Yew Dell Botanical Gardens (near Louisville, KY): USING AN OUTDOOR "SEED COFFIN":"We have an excellent 'seed coffin' that we use for seeds like this. It is a 24 inch tall box, 3 feet wide and 8 feet long. Sides are pressure-treated plywood. Bottom is open but covered with quarter-inch hardware cloth and a second layer of window screen. Tightly fitting, hinged lid is framed with light-dimension lumber around the edges and covered with the same hardware cloth and window screen material as we use to cover the bottom. Box is set 6 inches deep in the ground and then filled with about 12 inches of sterile bagged potting mix mostly pine fines.2021 Advice from Jeff Morris, North Carolina: POSSIBLY DO NOT WASH OFF THE SEED COAT
"For seeds of varying germination requirements, we line out the seeds under about 1 inch of pine fines and let them be. Then, as seedlings emerge, be it after a week, a month, a year or several years, we simply pluck out and pot up the seedlings to individual pots. Works like a charm! Seeds are subject to natural temperature and moisture fluctuations, and they germinate when they want rather than when we think they should germinate."
Note: Torreya Guardians had sent Yew Dell Gardens a few dozen seeds several previous years. In 2017 we donated 400 seeds, sourced from the 2016 seed harvest in Medford, OR.Jeff wrote in an email 18 November 2021, "I believe that the 'plum' covering assists in germination somehow. Just food for thought." Connie reflects that the 500 seeds she received from Joe Facedola this fall for further distribution came in a plastic ziploc within a box in which the fleshy shells were removed (they fall off easily when ripe), but the slimey, lovely-smelling coating on the seeds themselves was still fully there and Connie intends to send seed packets without washing that material off.
Germinating Seeds at
Corneille Bryan Native Garden
LEFT: April 2013, Janet Manning holds a seedling she just liberated from the outdoor germination tray shown below. (Notice the wire grid alongside it, which hinges over the top of the tray to protect the planted seeds from rodents.) This particular seedling recently germinated from a crop of seeds harvested autumn 2011. Notice how there is still plenty of nourishment available in what remains of the seed to add growth both below and above ground without depending on sunlight to fuel that growth.
• ADVICE FOR REWILDING STYLE OF GERMINATION
Connie Barlow writes: Recent scholarship and experience suggests that there is great wisdom in advice from the past. For "rewilding" experiments in which Torreya is planted into regrowth, full-canopy deciduous forests, ideally the seeds are allowed to fully ripen on the parent tree and then plucked (from branch or ground) before squirrels abscond with them.
PHOTO LEFT shows ripe seeds (purple sarcotesta; not green) collected by Joe Facendola on 31 October 2020 from the ground beneath the tall mature Torreya in Clinton, NC. Joe suggested that the seeds had not yet been collected by squirrels because a severe windstorm occurred two days earlier. Observation of that tree suggests that gray squirrels are likely too heavy to be able to venture out to the branch tips, where all seeds reside. As well, getting there would be a very prickly adventure.
Note: Almost all of the seeds pictured here were distributed to volunteers in NC, IN, VA, WI, NY, MI, and OH. And nearly all were then FREE-PLANTED directly into forested habitats within one month. Speed of planting into permanent forest habitat is helpful because of (a) the tremendous powers of the embryo to epigenetically adapt to its surroundings during the months or years of its maturation prior to germination, and (b) the mysterious powers of endomycorrhizal fungal helpers to attach emerging roots into the "Wood Wide Web" that networks them with surrounding trees.
Connie also suggests ...
Follow the 1859 ADVICE OF H. W. SARGENT
Source: "A Treatise on the Theory and Practice of
Landscape Gardening Adapted to North America",
by H. W. Sargent, 1859
MONITORING AND REPORTING RESULTS
It is very important for planters of this highly endangered tree to both monitor and report results. Failures are just as important as successes to report as that is how our knowledge (and best practices) can advance.
MONITORING: Keep track of where you plant (especially if you are "free-planting" seeds directly into the ground. For a dozen or so seeds, stakes (and mapping) might be ideal. If you have many seeds, the easiest way to proceed may be to use flags. See the webpage of our Spring City TN planter as an example of flagging (400 seeds planted in just 2 days!). Easier is simply to note and photograph each specific slope, alcove, or other discernible topographical feature and just note how many seeds were introduced in each. Then enjoy in year 2, 3, and 4 simply scouting the area after deciduous forest-floor greenery has gone brown, during which time the evergreen torreyas are easily visible (unless camouflaged among the fronds of evergreen Christmas Ferns).
REPORTING: Annual reports are ideal. Photos with captions are recommended. Full-scale photo-essays in pdf are ideal. Know that keeping track of context (plant associates, overhead canopy) and anything else that might help distinguish factors that favor different planting micro-sites are very important. Hypotheses for interpreting causes of results are also encouraged. The most sophisticated reporting style as of 2019 is that of the Stovers in Greensboro NC, who freeplanted seeds beginning in 2013. Sample their January 2019 report in pdf.
2011 Advice by Buford Pruitt, Torreya Guardian grower in Brevard, North Carolina:
EXPERIMENTING WITH SEED GERMINATION AND NUTRITIONAL SUPPORT: After having only 1 in 10 seeds from a 2010 seed harvest germinate, Buford wrote on his blog about changes he made for germinating the 10 new seeds he received from the 2011 harvest:"I have planted them in 1-gal pots again, but with several significant differences. I used organic potting soil made from pine bark and chicken run sawdust, which doubtless contains a lot of (hopefully slow-release) nutrients, whereas the last group was planted in a 1:1:1 ratio of perlite, vermiculite, and peat moss. The new group received a dollop of dolomite (lime) in each pot, whereas the first group did not. I scarified the new group' seeds by sawing a small groove just through their hard shells with a Dremel tool, whereas the last group was not scarified. This time I plan to use organic fertilizer instead of the previous year's chemical fertilizer. The seeds this year are planted 2 to a pot rather than 1 per pot. They will be watered by hand this year with de-chlorinated water rather than by chlorinated water via soaker hose."
"Finally, I received the seeds this year in time for them to get a whole winter outside rather than last year's less-than-half a winter. This year the potted seeds again will be kept outside to experience the cold winter's temperature extremes (this is called 'stratifying'). The pots are sitting directly on the ground so they can be inoculated by native soil microbiota, the pots are located where they will get morning sunlight and afternoon shade, and the pots will be kept in a hardware cloth box' to ensure that rodents don't eat the seeds."
LEFT: "Here is what they look like so far, with the 5 pots ready for sequestering under steel mesh and the sole seedling from last year at the upper left, outside the box:"
Editor's note: As of October 2012, 3 of the 10 seeds that Buford received from the 2011 harvest have germinated. As of February 2013, 9 of the 10 seeds he received from the autumn 2011 harvest germinated; several germinated during winter months at his northern Florida residence. See his blogpost with photos.
BUFORD PRUITT reports (Aug 2013) on the status of the 2012 harvest seeds he is trying to germinate:
Brevard, North Carolina Torreya page TOP TWO PHOTOS LEFT: "Here are two photos of damage to two growing tips of a germinating Torreya seed. I guess they are roots, as I seem to remember reading that roots are the first meristems to sprout from Torreya seeds. The tips of the two growths were found to be damaged when I dug the seed up this morning, even though I was careful not to damage it myself. It looks like the tips have been eroded away rather than chewed off. Nematode damage is often presented as occurring within nodes along the length of roots, so I don't suspect nemas as the culprits."
UPDATE: "Today I took apart my two remaining 4-seeded 2012 pots. Each had two healthy seedlings and two unsprouted seeds. I re-potted the four seedlings into fresh potting soil and set them back under the hardware cloth. Both of the first pot's unsprouted seeds had in fact germinated, but their growing tips were abraded off like the one I reported Saturday. There was an ANT NEST in that pot, and I saw an ant and an ant larva nestled within the remaining limbs of one of the sprouts. It appeared to me that the ANTS had chewed off the growing tip, arresting its growth, which I suspect will kill the seed. One of the other pot's two unsprouted seeds had not yet germinated, which I planted in its own pot, and the last seed was a repeat of the first two.
In summary, ANTS OR ANOTHER UNKNOWN AGENT infested three of five 1-gal pots and killed 4 of 19 sprouting seeds, for a 20% rate of mortality. This pest reduced my germination success from 95% to 75%.
PHOTO BOTTOM LEFT: "Look at the attached photo of a normal, healthy seedling sprouting node. You can see the dark seed, the leafstalk extending out to the upper left, the roots to the lower right, and a vague node from which radiate the roots, leafstalk, and twinned stalks that connect the node to the seed. Evidently, from the seed first emerges a twinned stalk about a quarter-inch in diameter that grows about a half-inch horizontally and then makes a 90-degree bend downward that extends another half-inch or so. From the tip of the twinned stalk then emerge numerous roots that grow outward and downward from the exterior of the node, and a leafstalk that emerges from between the two sides of the twinned stalk and grows straight up. Because both the leafstalk and roots emerge from the node, I'm not sure that what first sprouts from a T. taxifolia seed is technically either a root or a shoot.
PROGRESS REPORT: I now have five 2011 seedlings in the ground (in Brevard) in addition to the sole 2010 seedling. Based on previous experiences of TGers, I have not planted any under a full forest canopy. All are at edges of openings in the forest where they will get several to many hours of direct sunlight each day.
Click left to watch VIDEOS filmed in spring 2016 of Buford Pruitt showcasing each of his torreya specimens growing in his forest at Brevard, NC.
All UPDATES at Brevard NC torreya page.
2013 Advice by Jeff Morris: (Also consult Jeff's ongoing photo-illustrated webpage of his Torreya propagation work.)
Of 17 new seeds planted in a three-gallon container in autumn 2011, 9 have sprouted by spring of 2013, 2 appeared to have been nibbled away by a mouse in the greenhouse, and 6 others have not yet sprouted.
So I replanted those unsprouted six. The method I used in October 2011 was to cut a bubblewrap roll to about 6' width, and roll up sandy-clay-vermiculite soil in with a seed each 6". Then I placed the rolled mixture down in a 3 gallon pot on the concrete floor of the greenhouse, where it got partial sun and was watered about once or twice per week.
Also, the 3 dozen or so seeds I harvested last fall (from my own Torreya taxifolia trees) were stratified in the fridge alternating a week in, a week out, until about early February, when I put them back in for two months. I planted those in 5"-deep seed trays and put them under rabbit wire in a specially made box, where they are kept moist with waterings twice a week in a mostly shaded area of the patio.
Never artificially fertilize the potted seedlings! I prefer to use Miracle Grow Garden Soil in the pots not "potting soil".
Here are the basic phases I put the seedlings through before planting:(1) First, I roll the seeds up with local soil in bubble wrap cut into a 6" wide roll, with about 1" of soil covering the top of the seed, and seeds about 4" apart; then I roll up the mixture and place it into a 1- gallon pot and keep it watered as needed.
(2) In 6 to 30 months, the seeds sprout and I unroll the 2" or so tall seedlings out, with their 3" or more root system, which is spread across a flattened concave plane between bubble wrap layers. (I use bubble wrap because it is a vapor barrier, and permits light to reach the freshly sprouted seedlings below the surface, too.) This is the stage where I transplant each seedling into its own 1-gallon pot, using the mixture of 1/2 Sta-Green Garden Soil, 1/4 Coarse-grade Vermiculite, 1/8 sand, and 1/8 local soil. I even will mix in a slight bit of composted soil (containing coffee grounds, resinous decayed Pinaceae material, and banana peels in which abundant worms have been introduced) but carefully, as it is a bit high in nitrogen. The composted soil is added mostly to introduce the red night-crawler worms into the pot, which will provide an opportunity to feed the potted plant for the season with worm castings, which are a natural fertilizer.
(3) After a complete Spring and Summer growing season, just as the first roots appear in the weep-holes of the one gallon containers, I transplant the 1-gallon seedlings each into its own 3-gallon container, and use 3/4 Sta-Green Garden Soil and 1/4 local soil. This will take the seedlings through one more growing season.
(4) In October of the following year, the 3-gallon seedlings will be about 2 feet tall, and the roots will be partially visible at the bottom weephole. It is important at this stage to plant the sapling in the ground, or into a 5-gallon or larger container.
Editor's note: Torreya has a taproot; it is crucial to get the seedling into the ground before the taproot is "root bound" by a too-small pot. Jeff Zahner (Chatooga Gardens, Highlands NC) confirms the importance of getting seedlings into the ground at a young age because, "seedlings do not transplant well at all, being mostly taproots at a young age."
2015 Advice by Jeff Morris on importance of not blocking growth of the taproot:I recommend purchase of 4" or 6" thin-wall schedule 20 PVC pipe:
4-in x 10-ft Solid PVC Sewer Drain Pipe Charlotte Pipe 6-in x 2-ft Solid PVC Sewer Drain Pipe
You can cut the piping to desired lengths 16" to 24" to support tap root growth, and drill small holes for wire or fish line mesh bottom, and drop weed fabric or pieces of discarded tee shirts to hold the soil mixture in place. And before transplanting the seedlings into the piping containers, secure them upright, using a wood frame, or duct taping them together so that they remain in an upright position. Then water a few times over a couple days, to allow the soil to naturally settle.
Using this method, you can expect very healthy tap root development, which will result in more upright and narrow early growth of the sapling. And planting to the soil which should be done within two years after germination involves digging a hole, removing the mesh and cloth, and gently tapping the sides of the pipe with a hammer to allow the sapling to sink into the fresh hole.
When digging a hole to plant a Torreya taxifolia, I recommend that the hole be dug an extra foot deep, and drop small chunks (not sawdust) of evergreen conifer wood (pine, juniper, picea, abies, or taxus) laced with hearty portions of peatmoss about 8", then a 50-50 native soil / peatmoss mixture tamped in lightly about 4", before setting the container-grown plant in place. It gives the taproot a ready medium to continue to grow downward, which will support faster and more drought tolerant growth of the sapling. Mulch with small pine bark nuggets, and watch it grow!
VITAL! Encourage Symbiotic Mycorrhizal Fungi
Whether you choose to germinate your seeds in pots, seed beds, or one-by-one directly into the soil of their ultimate forest destinations as subcanopy trees, the seeds must be given habitat/soil conditions in which their mycorrhizal fungal partners are ready to immediately help the torreya grow healthy roots and root hairs.
The type of FUNGAL SYMBIONT that partners with Torreya establishes tree-like (arbor-like) structures within the root cells.
It does not reproduce by above-ground mushrooms, but individual spores within the soil surrounds.
LESSON: Because the fungal partners for torreya do not cast any spores into the air, the soil itself must harbor these non-mobile, long-lasting spores. Fortunately, many woody plants, herbs, grasses, and all ferns associate with the same fungal partners that Torreya requires. So healthy forests reliably contain plentiful fungal spores in the soil. But heavily tilled and played-out agricultural fields being recovered into forests may lack the necessary spores in the soil.
GENUS TORREYA, as a member of the primitive TAXACEAE family of conifers, partners below ground with the Vesicular-Arbuscular Mycorrhizae (VAM or AM) class of beneficial fungi. These fungi are of the "ENDOmycorrhizal" type, meaning the fungal cells penetrate the inside of individual root cells. Indeed, it is the fungus not the plant that grows the actual root hairs!
In contrast, the largest family of conifers, PINACEAE (pine, spruce, fir, hemlock) associate with "ECTOmycorrhizae" (ECM or EM). This mychorrizal type has the fungal cells living in between root cells (and sometimes covering the outside of the root), rather than living within the cells. The plant grows its own root hairs, and the fungal partners then become occupants. HARDWOOD EM TREES include oak, hickory, birch, basswood, poplar.
"Dr. Melissa McCormick (Smithsonian Environmental Research Center) final report of research into the mycorrhizal associations of Torreya taxifolia within its native range along the Apalachicola River in northern Florida and extreme southern Georgia and in several explants from northern Georgia into North Carolina determined that Torreya forms mycorrhizal associations with arbuscular mycorrhizal (AM) fungi. Nearly all AM fungi identified in this study belonged to the Glomus genus. Many species in this genus are known to have a role in protecting host trees against root pathogens. They found a similar diversity of AM fungi associated with native and explanted trees, suggesting that native populations have sufficient diversity of mycorrhizal fungi available to support healthy tree growth. They found that the abundance of mycorrhizal fungi in tree roots (including non-Torreya roots) was higher in garden explants (Atlanta Botanical Garden and Biltmore Gardens) than in native or forest explanted trees. This relationship was likely driven by light available to garden-planted trees to support photosynthetic fixation of carbon, which could then be used to support associations with mycorrhizal fungi. Within each habitat type (garden, forest explant, native), they found that Torreya roots were more heavily colonized by mycorrhizal hyphae than the roots of surrounding trees, suggesting Torreya are strongly dependent on mycorrhizal fungi." from the "Comments" column of Reports page of the official U.S. Endangered Species Torreya documentation (p. 2, accessed online by Connie Barlow March 2022)WARNING: TORREYA (and other ENDO-dependent plants) must gain mycorrhizal partners in order to grow ROOT HAIRS.AM WOODY PLANTS (good for Torreya): Tuliptree, Sweetgum, Maple, Buckeye, Walnut, Catalpa, Cherry, Elm, Dogwood, Gums, Hackberry, Hawthorn, Holly, Locust, Honeylocust, Hophornbean, Magnolia, RedbudWARNING: Stay away from ericoid plants (Rhododendron, Azalea, Vaccinium) which not only associate with unique mycorrhizae but often indicate acidic soils.
AM HERBACEOUS PLANTS: Ferns, Blackberry, Lily, most flowering herbaceous plants
WARNING: Do not plant torreya near EVERGREEN canopy and subcanopy plants. Late fall and early spring FULL SUNLIGHT CONDITIONS in deciduous forests are crucial times for subcanopy photosynthesis.
HEALTHY ROOT SYSTEM
LEFT: This seedling has emerged during its second summer in a rodent-protected germination bed within a semi-shaded forest setting. Before the above-ground growth became visible, the food energy and nutrients stored in the large seed supported growth of a taproot and some lateral roots, while encouraging symbiotic fungal partners to create the root hairs by feeding them food stores, too.
UNHEALTHY ROOT SYSTEM
RIGHT: Although the evergreen leaves (not visible) of the above-ground growth look healthy, the root system, even after 5 years in its germination pot, show an utter lack of root hairs and bottoming-out of the taproot.
LESSON: If you choose to germinate seeds in pots of potting soil or in ground locations other than healthy forests, INOCULATE THE SOIL WITH COMMERCIAL MYCORRHIZAL PRODUCTS.
PHOTOS BELOW: Lamar Marshall aimed for FULL-SUN ORCHARD STYLE placement of his seeds directly into his area of mowed lawn. He chose Bio-Tone Starter Plus to ensure that his mixture of top soil, sterile potting soil, leaf litter, and a pinch of lime will offered the torreya seedlings ready-to-go spores of ENDO mychorrizal fungal symbionts.
Lamar's terrier dog, Scout, does a fine job of chasing away the squirrels and eating the voles.
Lamar explained that Scout gives a distinctive bark at rodents, signifying that he needs to be let out to do his job.
Visit Lamar's ongoing PHOTO-ESSAY of his torreya plantings in Cowee Valley, NC.
MYCORRHIZAE DELIVER VITAL MINERALS: Whether ENDO or ECTO partnerships are forged, very few plants can survive much past the seedling stage if beneficial root fungi are absent. Fungal partners are crucial for extracting phosphorous (and usually nitrogen, too) from the soil and bringing it into the plant's roots. As well, root fungi whose hyphae grow connections that extend into the whole forest network of interconnected fungal tubes, the WOOD WIDE WEB, are capable of delivering photosynthates (sugars) to the growing seedling especially if the seedling accesses very little sun and thus absolutely requires supplemental sugars after the riches of the seed itself have all been used up.
GIFTS OF SUGAR delivered to the Torreya ultimately come from the full-sun canopy trees that produce sugars in excess. Scientists have not yet determined whether the locus of agency for determining whether an emerging seedling does or does not receive supplemental photosynthates resides in the plant neighbors who create the sugar or, more likely, in the immense, interconnected, and very long-lived fungal web for which successful "gardening" entails ensuring that some new seedlings are assisted in growth long enough to access shafts of sunlight themselves.
RECIPROCITY RULES: Ultimately, the seedlings given a head start by gifts of sugar delivered via the fungal network must reach a point in which they can (a) access sunlight to make their own sugars or (b) halt growth while waiting for the environment to change (e.g., a canopy branch or tree falls which opens up light). The seedling/sapling must be able to find sunlight and make its own sugars not only to grow itself but in order to feed the fungal cells within its roots. Both partners, plant and fungus, must ultimately benefit from the association, or the partnership will be lost. Fungi provide the MINERAL NUTRIENTS (and sometimes also water in a drought). But the plant must reciprocate by FEEDING SUGARS TO THE FUNGAL CELLS.
"Mycorrhizal networks are important for seedling establishment in perennial vegetation. The fact that seedlings that germinate in perennial communities, with existing mycelial networks, often become quickly colonized by mycorrhizal fungi (e.g. within 3 to 6 days after seedling emergence) is probably very important because small seedlings then have immediate access to a low-cost 'nutrient adsorption machine', provided and maintained by the surrounding vegetation." Marcel Van der Heijden et al., "Mycorrhizal Ecology and Evolution: The past, the present and the future", 2015, New Phytologist
CLICK ON THE ABOVE IMAGE TO ACCESS A HIGHLY RECOMMENDED REVIEW PAPER.
EPIGENETIC CLIMATE ADAPTATION
VERY IMPORTANT!!! It makes a difference what climate a Torreya seed experiences during the months (and sometimes years!) while the embryo is slowly maturing, prior to germination of the rootlike "radicle."
ADVICE FOR TORREYA PLANTERS: If you live in the southern or central Appalachians, it is surely fine for you to purchase and plant nursery-grown seedlings from more southern states (such as South Carolina and Georgia).
But if you live in the northern states, it is important to acquire seeds directly and put those seeds into the outdoor ground ("freeplanting") so that they can experience a full winter at their ultimate destination prior to embryo maturation.
Recent research (as in the research paper above) on commercially valuable conifers turned up surprising abilities of seeds to permanently shift the ultimate budburst timing in the spring and vegetative hardening in the fall. Because this has nothing to do with changes in the seed's DNA, it is called "epigenetic" adaptation, not genetic.
So, for northern-state planters, if you germinate seeds in your refrigerator (a basement is not cold enough), or if you purchase potted seedlings from a southern state nursery, your torreya trees may permanently be less capable of thriving in your climate than they would have been had you put seeds directly into their ultimate destinations in your forested property.
GENUS TORREYA might have even more exceptional epigenetic talents than the younger Pinaceae conifers that have already been tested. Consider the abstract from the paper (which you can click on to read in full):ABSTRACT: Conifers are evolutionarily more ancient than their angiosperm counterparts, and thus some adaptive mechanisms and features influenced by epigenetic mechanisms appear more highly displayed in these woody gymnosperms. Conifers such as Norway spruce have very long generation times and long life spans, as well as large genome sizes. This seemingly excessive amount of genomic DNA without apparent duplications could be a rich source of sites for epigenetic regulation and modifications. In Norway spruce, an important adaptive mechanism has been identified, called epigenetic memory. This affects the growth cycle of these trees living in environments with mild summers and cold winters, allowing them to adapt rapidly to new and/or changing environments. The temperature during post-meiotic megagametogenesis and seed maturation epigenetically shifts the growth cycle programme of the embryos. This results in significant and long-lasting phenotypic change in the progeny, such as advance or delay of vital phenological processes of high adaptive value, like bud break and bud set. This phenomenon is not only of important evolutionary significance but has clear practical implications for forest seed production and conservation of forest genetic resources. The underlying molecular mechanism that causes the 'memory' in long-lived woody species is currently under investigation. Here we summarize the information related to epigenetic memory regulation in gymnosperms, with special emphasis on conifers.
BEWARE OF RODENTS!
• OVERALL CUMULATIVE ADVICE (as of 2022):
1. NEVER PLANT NEAR FALLEN WOODY DEBRIS. When you find a good site for planting under a deciduous canopy, with well-drained soil (no clay pan and best if on a slope), then look around and notice where there is fallen woody debris. Do not plant anywhere near a log, or where several large branches are nearby. Small rodents will selectively choose these sites for making tunnels. If you are skeptical of this advice, you can experience the hidden tunnels near such sites, by using the table-knife testing tactic (below) in such an area yourself.
2. USE A TABLE KNIFE TO TEST FOR HIDDEN RODENT TUNNELS. When you think you have a good site to plant either a seed or a potted seedling, then use a table knife to poke the soil a number of times at and a bit outward from the spot. But first, make sure you can "feel" the difference between solid ground versus a tunnel below. (So poke around an area with woody debris first to train yourself to notice the feel of a tunnel.)
3. CLONAL PLANTS MAY BE TUNNEL-FREE. It is possible that evergreen clonal plants may largely or fully deter rodent tunneling, and thus offer a relatively secure place to introduce torreya:
LEFT: A seedling that germinated freely in a massive invasive ivy patch stretching out from an unmaintained zone of next-generation torreya saplings (Biltmore Gardens, NC).
BELOW: A patch of native Galax urceolata in the S. Appalachians. Connie Barlow was new to free-planting seeds, so she didn't know how crucial it was to plant the seeds 4 inches or more deep. The seedling depicted in both photos was the only of the seeds she free-planted that escaped either early seed-predation or later root disruption or vegetal browsing several years later. (Many of the seeds she planted under rocks did escape predation, and some of those escaped lethal levels of browsing, too.)
Two other genera of evergreen clonal herbs native to the eastern USA might also dissuade rodent tunneling, while offering torreya shared access to their arbuscular mycorrhizal network: Asarum and Shortia.
LEFT: This torreya seedling exhibits 3 or 4 growth spurts and no browsing damage, which is unusual. An immediate hypothesis is that the leaf pattern of the evergreen Polystichum fern camouflages the torreya sufficiently to prevent browsing by deer.
A supplemental hypothesis is that there may be something about the root system of the fern that also dissuades rodents from tunneling.
4. WHEN PLANTING POTTED SEEDLINGS, MAKE THE ROOT ZONE UNATTRACTIVE TO RODENTS. An absolute rule that Torreya Guardians have learned the hard way is to ensure that the soil immediately surrounding the roots of an outplanted potted seedling is no more attractive to ground-living rodents (voles and chipmunks, primarily) than the surrounding soil in place. Steps to take:• PLANT BARE ROOT. Shake the loose potting soil off the roots before planting, and use the same soil in the hole that you find in the immediate vicinity.PHOTO BELOW was taken in Spring 2016 by Connie Barlow at the Corneille Bryan Native Garden (Junaluska) site at Lake Junaluska NC. That was where Torreya Guardians had planted 10 potted seedlings in July 2008.
• MIX GRAVEL INTO THE ROOT AREA. If the surrounding soil is so poor that you must use better soil, consider choosing a site with better soil. If that is not possible (if the root soil is looser than the surrounds), introduce small pieces of local rock or gravel to dissuade rodents from entering.
• GO LIGHT ON THE MULCH. Thick mulch (especially woodchips) can be very attractive not just to tunneling rodents but also to those seeking a home base. Do spread some dead leaves over the clear zone, but refrain from creating a thick layer.
• ENSURE THE SURROUNDS ARE UNATTRACTIVE TO RODENTS. The two photos below were taken from a 2016 VIDEO of an outplanting of large potted seedlings in Brevard, NC. Advance to timecode 13:59 to witness the autopsy. There you will learn that the potting soil was not shaken from the roots prior to planting. You will see straw bales are right next to the planting. And you will hear Connie speculating about whether seasonal use of a birdfeeder nearby likely encouraged a population build-up of rodents that could not be sustained in the off-season. You will also see an insert at timecode 18:27 where Connie shows photos and video of two other rodent-killed out-planted seedlings (at Lake Junaluska, NC), also in 2016.
The photo shows a rodent tunnel and rodent-gnawed roots of what, until Winter 2015, had been a vibrant little Torreya. A second such planting was discovered likewise killed the same day. Both can be seen here:
Previously, 3 Torreyas had been killed by rodents their first winter. All 5 deaths are in the plantings closest to a set of bird feeders at a seasonally occupied home. Equally important is that one can see tiny specks of perlite in the loose soil of the photo left.
• 5. AVOID HOMEGROUNDS OF CHIPMUNKS, GROUND SQUIRRELS, AND WOODCHUCKS. Although this idea has not been tested, it is possible that these large rodents instinctively "manage" their home territories by removing tree seedlings that would create shade conditions unfavorable to their food items if left to grow. As their preferred habitat within woodlands has large openings in the canopy to ensure habitat for their preferred foods, it may be unusual to encounter them in most settings chosen for planting torreya, except by orchardists seeking full sun for fast growth and seed production.
MORE DETAILS ON SAFEGUARDING AGAINST RODENTS
It is crucial to shake off the good soil in the pot and to ensure that it is no better (looser) than the soil in the surrounds where you plant it. Jack Johnston suggests introducing small pieces of shale and/or gravel into the soil you use to fill the hole when planting it out. Newest discovery (Connie Barlow plus Clint Bancroft in TN) is that one must not plant seeds nor potted seedlings anywhere near logs or branches on forest soil. They are automatic homes or safe passages for voles and chipmunks.
BEST PRACTICE: Plant no seeds nor seedlings without first testing the soils in the surrounds with a table knife. It is easy to "feel" when the knife hits a hidden tunnel.
We have had several reports of squirrels digging up Torreya seeds from pots left outdoors. These are rodents that have no prior knowledge of what Torreya seeds smell like, nor that they are tasty. Click here to see the wire-mesh protected outdoor seed bed that Jack Johnston constructed for Torreya seeds after voles had dug under the surface mesh to raid the seeds.
NEVER PLANT TORREYA WITHIN 100 YARDS OF A BIRD FEEDER. Dropped seeds may foster a giant population of squirrels, chipmunks, and voles. Read about the problem of a bird feeder near the torreyas at Lake Junaluska NC.
Consider when free-planting that there may be little or no surface evidence of a forested microsite that is actually riddled with vole tunnels.
To avoid such places, use a TABLE KNIFE to test all around your chosen microsite to ensure that there are NO NEARBY VOLE TUNNELS.
Also, avoid sites near fallen trees or branches, which are attractive to rodents.
2018 UPDATE: From now on, anyone "free-planting" seeds directly into forest soil with no cage protection (or overlying rock protection) should plant seeds 5 inches deep! Rodents apparently cannot detect them that deep, and three planters in 2017 reported that the large seed has no trouble sending a shoot that far upward before reaching light (ditto for seeds sending shoots long horizontal distances to get beyond the overlaying flat rocks).
Alas, even 8 or more years after growing in open or forest soil, small Torreya trees are still vulnerable to ground-burrowing rodents that kill the trees underground by nipping off small roots and completely gnawing off bark (presumably for food value) of large roots in the upper soil layer. Wire cages protecting lower stems do not protect against below-ground gnawing. While there is no fail-safe way to guard against burrowing rodents, you can make the soil less attractive to rodents by (a) shaking off the perlite/potting soil mixture when out-planting a potted seedling and (b) having the surrounding "mulch" layer be no different than that found in the immediate surrounds.
2018 UPDATE: Jack Johnston (GA) and Clint Bancroft (TN) suggest that, when outplanting potted seedlings, it is a good idea to add gravel and/or pieces of shale to the soil mix. This makes the soil around the torreya roots and stem even less attractive to burrowing rodents than the surrounding forest soil!
Editor's note: Thanks to our New Hampshire Torreya Guardian, Daein Ballard (see section below), we can now suggest that care must be taken to shake out perlite and loose soil from the roots of potted seedlings prior to planting outdoors. Chipmunks will be enticed to build their winter burrows in the loose soil (and therefore snack on the roots too) especially if the natural soil in the surrounds is inferior or has a clay pan barrier to digging. The same goes for mulch: Mulch around the base of a torreya will also attract burrowing rodents.
Note that in the Brevard instance, the potted seedlings had been outplanted with their potting soil mixture intact around the roots. This loose mixture is very attractive for rodents to make their winter burrows, while feasting on roots. (Read below Daein Ballard's observations about chipmunks overwintering in burrows made in potted-soil Torreya outplantings.)
So we have learned the hard way: Shake off the perlite before planting out. Note that this problem of out-planting soils being more attractive than the natural soil can be alleviated by directly planting seeds into the outdoor soil ("free planting") exactly where you hope they will keep growing but free-planting has its own substantial rodent hazards that require specific actions to curtail.
RODENT ADVICE BY CONNIE BARLOW & COURT LEWIS: Plant seeds 5 inches deep
July 2017 news from Court Lewis (along with photo):"I had begun to think that the seeds I planted without protecting cans had been eaten or were too deep. But they've just started coming up. I had them at 5 inches deep compared to 1-2 inches in the rodent-protected cans, so it just took them longer. Also, lately we're been having heavy rains, after a long dry period. Torreya seems to like our orange clay-ey soil in East Tennessee."Notes from Connie:• Court received seeds in the fall of 2015, from the harvest that year.
• I began advocating in 2015 for seed planters to experiment with out-planting seeds directly into final locations in forest habitat, unprotected, except for testing whether 5 or 6 inches deep is adequate for preventing rodents from detecting them, while still allowing the germinating seeds to rise up to the sunlight. This report by Court Lewis, who lives in NE Tennessee, near the Cherokee National Forest, is the first report of successful experimental results.
RODENT ADVICE BY DAEIN BALLARD (New Hampshire torreya planter)
PROTECTING SEEDS FROM RODENTS: The most destructive animal around here to the seeds are Chipmunks. It seems once a Chipmunk has found one Torreya seed they search for them preferentially and eat them all wherever they can find them.
As for the seeds I've been sent, I've been using your small-stone method to protect them. I've lost almost all the 1st-year seeds I didn't protect this way to Squirrels, Chipmunks and Voles. None of the 2nd-year seeds I planted have been touched, though, even without protections. My hypothesis is that the 1st-year seeds are very fragrant and the 2nd-year seeds have almost no smell at all; so the animals can't use their noses to find them.
PHOTO LEFT: Biodegradable mesh cage protects out-planted seedlings from rodents and deer by extending 3 feet above ground and also from burrowing rodents by extending 1 foot below ground. (Photo by Daein Ballard)
PROTECTING OUT-PLANTINGS OF POTTED SEEDLINGS FROM RODENTS: It seems like it's a good idea to sink any protective cages into the ground when planting a potted Torreya. My observation has been that rodents target trees planted from a pot because the surrounding soil is relatively loose and easy to dig in. To compensate for this I grew my seedlings in narrow, 1-foot-deep pots (made for trees with taproots). Then when I planted I used durable (but biodegradable) tree cages 3-foot high and sunk them 1-foot into the ground to protect the seedling's roots from rodents.
I planted Jeff's Torreya and the rooted cuttings I got from Nearly Native Nursery directly into the ground without cages (due to the size of the pots) and have been fighting to keep chipmunk's burrows away from them ever since. I planted those trees in my yard, though, so it's easier to keep an eye on them and protect them.
I have found numerous occasions where rodents attempted to dig the protected seedlings up but failed because the protective cages were sunk as deeply into the ground as the seedling's roots.
I also found that it's a good idea to flank the seedling with two sticks/branches 4-feet long, stuck into the ground on either side. Otherwise, deer tend to stomp on the seedlings, because the 3-foot plant protectors are just below their vision.
Using these methods I've only had one seedling die back thus far (of the 30 or so total Torreya I've out-planted), and that was due to my son stepping backwards onto it while he was helping me plant other things in the woods.
DAEIN'S CHIPMUNK STORY: I've been fighting to keep a chipmunk (probably the same one that nipped off the other cutting's lower branches) from making a burrow right next to another rooted cutting that I had nurtured in a pot and then outplanted. Chipmunks tend to be like voles: They live in their burrow during the winter. They wake up every few days and eat some of the food they have in the burrow nearby tree roots included!
I've been working hard to get the chipmunk's burrow away from the Torreya before winter. I've dug its burrow up numerous times, and each time he redigs it right next to the tree. The other day I cut a hole in a tarp and laid it over the tree with it poking through the hole to make it impossible for the chipmunk to dig his hole near the tree. Well, today I found the chipmunk dug a new hole near the tarp which quickly turned under the tarp after going down a few inches. I decided to dig up the tree so I could get under it and put in some protective mesh layers to keep the chipmunk out.
Well! Upon digging up the tree I quickly discovered the chipmunk had already eaten the roots! No wonder the tree has looked so bad for the last month! Since the tree itself is still alive and it also still has a bit of a stump with a couple roots, I've put it in some damp perlite in the basement in an attempt to reroot it. Hopefully it makes it.
Notes:1. I germinated the seeds in a strip of those large rectangular packing bubbles. I cut the ends off, filled each with the germination medium, and added one seed. Then I poked a lot of holes in the bottom and put them into trays. I did this so I could monitor their germination and early root development very closely. As each one germinated I transferred it into the 13"-deep, narrow tree pots (the depth of which would encourage taproot growth.
2.. I bought the tall, narrow pots from this website: http://www.stuewe.com/products/treepots.php
3. I bought the biodegradable mesh tree protectors online from Gempler's.
RODENT ADVICE BY FRED BESS (Ohio torreya planter)
PROTECTING NEWLY SPROUTED SEEDS FROM RODENTS: "I experimented with germinating the seeds together, with full rodent protection. Then I planted them directly into forest soil. The result: Every single one of them had been dug up by chipmnunks. It seems that this method of planting (shortly after germination) is a bad idea unless extraordinary means to protect the seeds are used. I do have several plants almost a year old (photo below) whose seed has been exhausted of nutrients, so I think these can much more safely be planted without the vermin disturbing them."
PHOTO LEFT: These are Torreya seedlings spending one final winter in Fred's greenhouse. They will be out-planted spring 2017.
Fred has discovered that seedlings outplanted their first year of germination are usually root-killed by rodents (as the large below-ground seed still contains plenty of nutrients).
But by their second year the seed is virtually empty, hence rodent predation is merely vegetative bud nipping (which damages but does not kill the plant).
WHY RODENTS PREFER LONG-DORMANCY SEEDS
and thus TORREYA is extremely desirable
PHOTO: October 2021 was a "mast year" for white oaks in southern Michigan. Owing to rainfall, the acorns germinated almost immediately and the radicle/root system grew at an immense pace before Connie Barlow could gather the seeds and plant them.
Acorns of most species of "white oak" will germinate within days of falling off the tree, if moistened by rain or dew. The radicle will grow an extensive root immediately, but no above-ground shoot begins to grow until the following spring. This behavior ensures access to groundwater in the spring to support above-ground shoot development, even if rainfall would otherwise be inadequate.
Researchers have documented the ecological pros and cons of AUTUMN germination of WHITE OAK acorns v. SPRING germination of RED & BLACK OAK acorns:• STORAGE PREFERENCES BY SQUIRRELS. Tree squirrels (such as the gray squirrel of North America) will consume WHITE OAK acorns as soon as they fall and in early germination, but they will almost exclusively gather, carry, and bury RED OAK acorns. The reason is obvious: only RED OAK acorns will remain ungerminated and thus intact underground throughout the winter and thus remain viable as food. If WHITE OAK seed abundance is high and RED OAK low, squirrels will bury WHITE OAK acorns but first they will remove the embryo so that no root development extracts food value from the seed.
• WHY TORREYA SEEDS ARE PREFERRED ABOVE ALL ELSE: Because most Torreya seeds will remain ungerminated throughout the summer (and possibly through the next winter or longer), burying torreya seeds in the autumn ensures a long-lasting food source that no oak or maple or beech can offer.
Learn more about the remarkable abilities of squirrels to sense by smell the oak type of an acorn, its viability, and whether weevil larvae are embedded (and thus will destroy) an otherwise intact shell: "The Proximate Basis of the Oak Dispersal Syndrome: Detection of Seed Dormancy by Rodents", by Michael A. Steele et al, 2001, American Zoologist
PHOTO LEFT: Mid-June 2016 the right-most seedling in the pot shows new-growth trending to become the new main stem, following previous herbivorous destruction of the main stem apical leader.
PHOTO RIGHT: October 30, 2016 shows the same seedling on the day it was planted out into wild forest. It is photographed from the same angle as photo left. See that the spring new growth has now matured into vertical apical growth. But notice that the nipped-off stem also produced new apical growth from directly beneath the nipped-off top. So now there are two apical stems.
LESSON: Trust your seedlings to recover from even severe apical herbivory!
ABOVE: Two seedlings donated by Jim Thomson (Cullowhee, NC) to Bob Miller of Loveland, OH, plus a free-planted seedling in Miller's forest. All show a new leader growing after herbivory removed the original apical tip.
ABOVE: Nelson Stover (Greensboro, NC) photographed this sequence of leader loss and recovery: Nov 2016, May 2017, and Nov 2017. The recovery happens by growing a new leader not only from the stem bust also as a basal sprout.
BEWARE OF SNAILS during germination
Torreya Guardian Lamar Marshall (Cowee Valley, NC) reported in 2015 that several of his Torreya seeds suddenly had their tops eaten off soon after sprouting above the soil line. At first he suspected cutworms, but then he discovered that nocturnal snails found the pots to be safe to lurk under during the day. So make sure you pick up the pots occasionally and search for snails! Lamar also counsels that if your pots are near mulch or wet cardboard (used in permaculture) or any other good habitat for snails, you should either move your pots or be very watchful. Note: The snail problem may be inapplicable when seeds are directly planted into forest soil.
Torreya Seeds Directly into Wild Forest Habitats
BENEFITS OF PLANTING SEEDS DIRECTLY INTO FOREST SOIL:1. MYCORRHIZAL ROOT HEALTH: Mycorrhizal fungi are not only beneficial for tree roots; the "arbuscular" ancient symbiosis that Torreya depends on is required for root-hair development. Access the mycorrhizae section of this webpage to learn which tree species utilize the same fungal partners and hence where best to site free-planted seeds. 2. EPIGENETIC ADAPTATION TO SITE: Recent research indicates that conifers epigenetically acclimate to different climates during the within-seed embryo maturation phase. This ancient tree genus has enormous capacities to epigenetically adapt to your climate conditions IF you put the long-to-mature seed directly into your outdoor ground before the rootlike radicle emerges. "Free-planting" seeds is thus an ideal way to achieve this helpful adaptive capacity. Go to the EPIGENETIC SECTION of this "propagate" page to learn more, if you wish.
3. EASY AND "SAFE": Traditional ways of assisting endangered plants is to first plant them in caged pots or wire-protected soil beds. This is time-consuming especially when the potted seedlings then require transport for outplanting into their final sites. Also, above-ground outdoor pots make the seeds vulnerable to deep-freeze winter episodes. Thanks to experiments by Torreya Guardians planters, we can recommend the following best practices for minimizing losses when "free-planting" seeds directly into their ultimate spots within forest contexts.
SUMMARY SEED-PLANTING ADVICE AS OF 2019
1. TO DETER SEED PREDATION: Plant seeds 4 to 6 inches deep. Flat rocks placed over a seed may also help, but the dangers of rocks are that they attract ants, may prevent the seed from accessing rain, and may force the germinating stem to circle around before finding a way to pop out the side (usually upslope). See PHOTOS of good and bad results at this section of our detailed free-planting webpage.
2. TO DETER ABOVE-GROUND HERBIVORY: Newly emerged stems and leaves are vulnerable to toothed herbivores upon emergence. Even when the needle-like leaf tips harden, deer and rodents may still nibble and sample. As a subcanopy-adapted tree, Torreya is usually capable of regrowing again and again, very quickly adding extra vertical stems (as well as regrowing lateral branches) so that the little seedling becomes less and less vulnerable to herbivory as the years pass. (See photos of herbivory recovery on our free-planting webpage.) As of 2019, we have several siting recommendations for free-planted seeds that will not be given any wire protection upon germination:2A. PLANT SEEDS WHERE DEER ARE LEAST LIKELY TO VENTURE: Possibilities include the slopes of deep and densely vegetated ravines, especially the steepest slopes you can find.
2B. PLANT SEEDS WITHIN THE OUTER REACH OF EVERGREEN FERNS. Fall of 2018, three locations documented that the only free-planted individuals that had escaped above-ground herbivory after 3 or more years were camouflaged during the winter by evergreen fern fronds. (See photos below.)
♦ FIND THE TORREYA IN THE PHOTO DIRECTLY BELOW:
The Torreya LEFT has the same camera angle as the photo ABOVE, so you can definitely find it on your own. This perfect little seedling showed no sign of herbivory. (December 2018)
This rural area of NE Alabama is a patchwork of cattle grazing and other fields, regrowth forest, and routine logging. Deer are not abundant and certainly not overpopulated here. But prints do turn up regularly in muddy sections of this forest.
This was the only one of 13 emerged seedlings camouflaged by Christmas fern fronds and it was the only one not damaged by herbivory. An added benefit of planting seeds very near ferns in general is that FERNS ASSOCIATE WITH THE SAME MYCORRHIZAL FUNGI AS TORREYAS.
• 2018 Documentation: Free-Planting Torreya Seeds directly into forest habitats
A NEW WEBPAGE of LEARNINGS by Torreya Guardians (posted December 2018) may assist the recovery of Torreya taxifolia in a very practical way: Assisted migration experiments can be implemented inexpensively:
More than a half-dozen Torreya Guardians began experimenting (as early as 2011) with "free-planting" seeds directly into their ultimate within-forest destinations. This new technique bypasses the labor-intensive, bulky, and potentially costly initial phase of poleward plantings that germinates seeds in pots or wire-protected soil beds prior to final planting (which, again, has often included wire cages for each specimen). In 2018 results were aggregated into a new photo-rich webpage, which will be updated ongoingly.
Results are presented in topical sections:
• Risks and Advantages of Free-Planting
• Learnings 1: Seed Harvesting, Storage, Germination
• Learnings 2: Techniques To Deter Seed Predators
• Learnings 3: Torreya Recovers from Herbivory
• Learnings 4: Siting to Minimize Above-Ground Herbivory
• Learnings 5: Siting to Minimize Antler Rubbing
• Learnings 6: Natural Seedlings in Historic Groves
Field documentation of the 6 seedlings that grew and survived with no human help, following "free-planting" of 15 seeds directly into forest soil in April 2015. Russ Regnery was the planter, within his forest at 3,800 feet elevation on the slope of Black Rock Mountain, near Franklin NC. Video clips of the 2015 planting (Episode 12) are matched with the actual seedlings closely photographed and analyzed Nov 2018. Results: Four summers later, this species exhibits remarkable capacities to recover from early stem and leaf herbivory.
Free-planting seeds directly into forested landscapes is best in years when we have plenty of seeds to spare, as in the autumn of 2015 when the Anderson family (Cumberland Plateau, TN) became a Torreya planter. Chris Anderson, pictured above, planted all 400 seeds either 3 inches deep or beneath a rock, directly into deciduous-canopy forest (including deep ravines). Flagging is an excellent way to keep track of where each seed is planted. The innovation in the above photos is that a second flag was added whenever an emergent Torreya was first seen poking up above the detritus or out from the side of a rock.
Watch a 2-part VIDEO of Chris Anderson taking Connie Barlow on a site visit to newly emerged seedlings, November 2017, title: "Florida Torreya to Cumberland Plateau: Rewilding an Endangered Tree", Part 1 (24 mins) & Part 2 (23 mins)
Overall, perhaps the IDEAL WAY TO PREVENT HERBIVORY OF NEWLY EMERGING SEEDLINGS is to choose sites in which deer are known to be rare. As of 2019 Shoal Sanctuary in northern Florida is in the lead for least herbivory of free-planted seeds essentially no herbivory on all 9 seedlings generated at sites of 40 seeds planted four years earlier. Watch VIDEO 31 (in 2 parts) for detailed visuals of the intact seedlings and their surrounds. THREE SHOAL SEEDLINGS are shown below:
ADDITIONAL ADVICE FROM TORREYA PLANTERS
PHOTO LEFT: Diana Spiegel (Dayton, OH) takes Connie Barlow on a tour of her free-planted Torreyas on 9 November 2017. In September she had noticed that 7 of the 12 seeds she planted spring 2016 (from fall 2014 seed harvest) were now 4 to 6 inch tall seedlings. All were planted on this south-facing forested slope along a creek south of Dayton OH, deciduous canopy.
Each seed had been planted 6 inches deep and was surrounded by a mesh of chickenwire also buried 6 inches (and staked). Confirming that Torreya seeds easily sprout at that depth is important news for future free-plantings seeking rodent protection via depth.
YET TO BE DOCUMENTED: Do seeds planted 5 to 6 inches deep do almost as well if no soil caging is used? If so, then we can fully recommend the easiest form of free-planting (that is, no cage and no rocks) so long as seeds are put at great depth?
CONNIE BARLOW EARLY EXPERIMENTS with FREE-PLANTINGEarly experiments (including FAILURES) are included here so that nobody wastes seeds repeating failed ideas.
♦ OCTOBER 2013 EXPERIMENT BEGINS:
Connie began planting some seeds directly into forested landscapes to test natural ways to deter squirrels from digging up the seeds. Below are photos of 3 methods I used: (1) carry a ROCK and place it over the top; (2) dig a hole sideways so the seed is buried under a LOG; and (3) cover the buried seed with a THATCH of interwoven branches.
THATCH (likely terrible)
♦ DEC 2015 PRELIMINARY RESULTS and Recommendations:
While all 3 methods appear to entirely deter squirrels, results vary for voles. Logs (and probably thatch) attract voles looking for shelter; who easily tunnel underneath. While voles can also tunnel under rocks, if the rock is not too big and especially if it is out in the open (distant from logs and branches), then a seed has a good chance of not being discovered by voles. Therefore, never plant seeds under or near logs!
Overall, only free-plant when you have an abundance of torreya seeds; likely only 20 to 50% of them will both avoid rodents and establish. So if you only have 20 seeds, do not experiment with free-planting. And if you do free-plant, record your actions and report back to us on what you have learned. We are still very much in an experimental phase. 2016 update: Connie's experience thus far suggests only 15% of seeds planted directly into soil (even far away from logs and branches) will yield seedlings, and perhaps 30% for seeds protected under plate-size flat rocks.
As well, if you are tempted to pick up the rock on occasion to see if germination is happening, that is probably okay. But never prop up the rock, not even slightly, if you see germination. Gently put it back down exactly as you found it. Here is why: In spring of 2015 I noticed that 3 rocks had short white beginnings of stems visible directly beneath the rock. (I always placed the rock initially so that the seed was precisely in the center.) For 2 of those, I made a bad choice: I propped up the rock about half an inch on one side, using sticks or small rocks. Six months later, only the unpropped rock had a stem emerging out into the air (and the other two had no evidence of any seed left). Note: The seedling always emerges from the upslope edge of the rock.
RECOMMENDATIONS FOR ADDITIONAL EXPERIMENTS:• COHABITING WITH INSECTS? Because I am unwilling to lift up the rock once I see a seedling emerging into the air, I do not know whether Torreya survives if ants or large hibernating beetles choose to live under the rock. Some rocks had insects under them; some did not when I peeked under them Spring 2015. I detect no pattern as to whether insects will be there or not. But it would be useful if someone discovered that Torreya actually can occupy the same rock as active insects.2018 UPDATE RESULTS: Daein Ballard (New Hampshire) reports that he found ants under all the rocks with ungerminated seeds free-planted. I responded: "My own experience leads me to suggest that rocks be used for rodent protection only on steep slopes where water seepage on the slopes means there is no dry zone under the rock for ants to take advantage of. Basically, from now on I recommend putting seeds 4 to 6 inches deep as the ideal method of free-planting.• PLANT SEEDS 4 INCHES BELOW SURFACE WITH NO PROTECTION? Thus far, I have planted all seeds either directly beneath a rock or only an inch or two beneath the open soil surface (hence, unprotected from squirrels and never successful!). It would be very useful to learn whether squirrels are unable to smell a deeply buried torreya seed. And given the size of seed, Torreya is likely capable of sending a stem outward (from a rock) or upward (from a deep hole) for quite a distance. This would be an important experiment to help us learn the safest easy method for free-planting. 2016 UPDATE: Spring 2016 I experimented with 6 pairs of seeds "free-planted". One seed of each pair got a flat rock over it (shallow planting below the rock); the other seed was planted 8 to 12 feet distant from its partner and 4 inches deep. I will report results. • PLANT ON A SLOPE. It is dangerous to cover seeds with a big rock on flat ground because (1) the underside will stay dry, owing to no down-slope seepage, so ants and even rodents may occupy the area, and (b) if there is no obvious side for the germinating radicle to grow "up" it may grow in ever-widening circles, eventually running out of energy stored in the big seed.
SUMMER 2016 UPDATE: October 2014 Connie Barlow planted 18 seeds freshly harvested that month into a private forest in southern Ohio. As of June 2016 three of the 18 were visible above ground, and the growth pattern indicated that the original vertical stem and leaves were already above ground sometime in 2015. See photos below for habitat context.
By June 2016 each seedling had fresh growth well established. All 18 seeds had been intentionally planted in a ravine on VERY STEEP SLOPES in full-canopy deciduous moist forest (with no rock protection placed over them). The intent was to ensure that no buck deer would be able to rub against a torreya sapling to dislodge antler velvet (as this is a big problem almost everywhere that torreyas grow). All 18 seeds were planted shallow in the soil, with no rock protection and all 3 successes are very near downed logs or large branches.
OCTOBER 2018 UPDATE: On our return visit (more than 2 years after the three photos above were taken), Barlow and Dowd managed to relocate the seedlings in the first and third photos. Both had evidence of significant rodent damage on apex stems but both showed terrific recovery. See 4 photos below.
PHOTOS ABOVE: Connie shows the same seedling as she showed in the image (blue shirt) above, two years earlier.
Close-up shows its recovery from a least two bouts of apical bud or stem herbivory.
PHOTOS BELOW: Michael finds the "two-log" seedling again. It, too, shows at least two bouts of apical stem herbivory.
BOTTOM LINE: Although this deep ravine slope may have prevented deer from venturing near the seedlings, notice how both were planted TOO CLOSE TO FALLEN BRANCHES OR LOGS! Only later did we learn to stay away from fallen woody debris.
VIDEO REPORT: Free-Planting Torreya Seeds into Wild Forest: 2015 best practices
Preliminary results from the 43 seeds of the 2013 harvest that were "free-planted" on the Evans property near Waynesville confirm that planting beneath flat rocks and beneath a thatch of branches were both effective in deterring squirrels. However, the results are mixed for voles. 47 minutes - filmed April 24, 2015, by CONNIE BARLOW.
CONNIE BARLOW (2015) cautions: "In April I visited the seed-rock combinations I planted at the Evans property in Waynesville fall 2013. What a disappointment! While I found 2 seeds happily sending down a taproot beneath their rock, and several more seeds showing no sign of cracking into germination, at least half of the sites showed vole tunnels under the rocks, leading to where the seed was. So planting under rocks, while totally deterring squirrels, serve as a welcome mat to voles. Not a good technique, unless we have lots of seeds." 2018 UPDATE: A big exception (as noted above) seems to be planting seeds (with no rock cover) on exceptionally steep slopes that seem to dissuade rodents from tunneling. Or, it is likely that planting seeds with rock cover on a lesser degree of slope enable moisture to penetrate and thus deprive creatures of dry homes. Overall best, however, is PLANTING SEEDS 4 TO 6 INCHES DEEP.
BOTTOM LINE: It is better to plant seeds 4 to 6 inches deep than to use a rock barrier.
FREE-PLANTING SUCCESS in Greensboro NC: Nov 2013 Nelson and Elaine Stover received and "free-planted" directly into their rural property a total of 30 seeds from two of our freshly harvested seed sources.
Exactly 2 years later (Nov 2015), they made a careful survey of their plantings and discovered that 6 of the 30 were now visible seedlings, including the photo at left. This is a success rate of 20%.
By 2019, the Stovers could confidently report that 50% of the seeds had germinated and none of those went missing after above-ground growth was recorded.
FRED BESS (Cleveland OH) stratified 150 seeds of the 2013 seed harvest over winter of 2014. He did this in damp peatmoss in his greenhouse and discovered that 27 of them had already germinated and begun to grow by MAY 2014. Thus a new possibility: By free-planting seeds in the spring (rather than in the fall immediately after harvest), they will all have escaped the first winter of possible seed predation.
December 2016 UPDATE: Fred discovered that even the spring-planted seeds were eventually entirely harvested by rodents as were any prompt out-plantings of very young seedlings whose seed (attached to the root) still contained nutrients and was not yet exhausted by plant growth. Note: Fred was unaware at that time that it was necessary to freeplant all seeds at depth.
Shade Or Sun?
• The 1986 recovery plan for Torreya taxifolia (its first) contains several paragraphs (below) indicative of preferences for site location beneath at least a partial canopy, ideally deciduous:
The sibling species of "Florida" Torreya is California Torreya. Connie Barlow made a site visit to 5 native locations of wild-growing California Torreya in 2005 to learn viable and preferred habitats of this genus. Young torreyas were found struggling in dense shade beneath evergreen redwoods (photo left, taken with flash) and growing vibrantly in full sun near a recent tree fall (photo above, Lee Klinger).
The fact that Torreya genus disperses a large seed suggests that it is adapted to beginning life in shade, which protects the seedling from drought and heat. Its survival strategy may be to play it safe in the shade of a mature forest and to wait for nearby tree to fall, to open up a patch of sun. Connie's observations in California indicate that only sunlit branches will produce seeds.
• Learning from California Torreya Habitats: Click for Site Visit by Connie Barlow in 2005
PHOTO LEFT: Sun-scalded Torreya taxifolia in Medford Oregon, February 2017.
Frank Callahan shows the sun-scald that suddenly appeared on these 20-year-old shrubby Florida Torreya trees (shrubby because they grew not from seed but rooted branchlets). The scalding occurred because these long-lived evergreen leaves had formed while two tall native pines partly shaded them: one on the south side and one to the west. Owing to drought and beetle kill, the two shade trees had recently been removed.
Connie Barlow filmed a VIDEO of these sun-scalded branches, which you can access at timecode 09:17 at "Florida Torreya Seed Production in Medford, Oregon (2017)".
Elsewhere in Medford OR, Frank shows two seed-grown Florida Torreya trees that have a normal tree form. The individual farthest from the shade of the house is showing evidence of sun-scald aggravated by reflection from light-colored pavement alongside. You can watch the VIDEO of Frank speaking about the sun scald at timecode 14:15.
• A 17 February 2017 email from Anita Koehn (soil scientist, USDA) interprets the PHOTO ABOVE this way: "My thought is that too much shade is more harmful then too little shade. However, once trees are shaded, it may be harmful to suddenly expose them to full sun because of the risk of photoinhibition. This is what probably has damaged the needles in the photo. Photoinhibition happens when the leaves or needles of plants receive more sun energy then they can process. The result is oxygen radicals that damage the photosynthetic apparatus in the plant. Normally, plants have protective mechanisms such as xanthophyll pigments, chlorophyll fluorescence, and other processes that capture the radicals and prevent the breakdown of the photosynthetic apparatus. Conifers are susceptible to photoinhibition in the winter when there are sunny conditions and they are still dormant so they can't use the sun energy. Their needles become more yellow and then green up again in the spring time." Note: Koehn is the author of Diurnal patterns of chlorophyll fluorescence and CO, fixation in orchard grown Torreya taxifolia.
ABOVE LEFT: Jack Johnston (2013) checks on his Torreya seedlings growing in full sun, North Carolina. (Each seedling is protected by a stacked wire cage.) 2016 UPDATE: Jack reports the Torreyas are growing very well in this "orchard" despite the severe 2016 drought. He weed whacks around each of the fenced seedlings yearly.
ABOVE RIGHT: Russ Regnery sits by one of his Torreya seedlings at 4,000 feet in North Carolina, planted in full sun near a forest edge. Russ partially shaded his seedlings from intense summer sun for the first several years and provided supplemental water. Experience suggests that if potted seedlings were grown in partial shade, but the out-planting site is nearly full sun (which is conducive to maximal growth, if water is sufficient), then partial and diminishing shade should be provided during the first few years, as Torreya needles are important photosynthesizers for the plant for at least 3 years. New growth will adapt to ambient conditions, but prior year growth must be accommodated.
ABOVE LEFT: Connie Barlow chose to plant the Celia Hunter Torreya Tree in mid-summer 2008 beneath the shadiest, moist slope she could find, as an experiment. Except for the first month after planting, this individual was never given supplemental water or any other kind of artificial assistance (as of 2021, it is still doing well, though it is slow-growing).
ABOVE RIGHT: In late November 2008, the Celia Hunter tree is fully exposed under overcast sky beneath this entirely deciduous canopy in the mountains near Waynesville, North Carolina. Connie's theory was that, unlike California where the canopy is evergreen hardwoods and conifers, the southern Appalachians are almost entirely deciduous. Hence Torreya taxifolia might grow well in the full sun of early spring and late fall, but be fully protected by canopy shade in summer heat and drought.
SUMMER 2016 UPDATE:
Michael Dowd stands over one of two specimens of extraordinarily healthy Florida Torreya near a giant White Oak, at Dawes Arboretum in central Ohio. It is noon in June, and notice the strong sunlight in the background. But here, that White Oak creates dense shade.
Do the Torreyas grow well here because they do most of their photosynthesizing in early spring and late fall, when the oak branches are bare? ...
Or is the Japanese Maple in foreground left the reason for their health? Genus Acer (maple) and genus Torreya associate with the same group of beneficial root fungi. Is it possible that some of the sugars produced by the photosynthetic leaves of the maple during the summer are directed by the fungi to the torreyas, and then the fungi depend on the torreyas to produce sugars when the maple is bare of leaves?
SUGGESTION: It is crucial for plantings of torreya in northern states (Ohio, Michigan, Wisconsin, New Hampshire) to ensure that torreyas are protected against subzero, desiccating polar winds. A border of mature Asian conifers provides 180 degrees of protection on the photographer's side of the photo above. In contrast, 2 torreya specimens planted in the arboretum at the same time, but exposed directly to the sky and/or an open northern exposure, had to be removed by the staff, owing to winterkill of most of the branches of each. This VIDEO recorded at Dawes Arboretum in 2015 shows these contrasting results.
Shade-Grown Seedlings Will Bleach in Full Sun
LEFT: Paul Camire in Capac, Michigan monitored this seedling in 2019 as -15F temperature ramped into -45 windchill.
Snow was too minimal (below the left-most branch) to offer any wind protection.
The dark green leaves made it through unharmed, and the light green new growth indicates that even the vegetative buds were unharmed.
IN CONTRAST, SUDDEN EXPOSURE TO FULL SUNLIGHT CAN KILL THE LEAVES. (See below.)
ABOVE LEFT (Capac, Michigan): A single day exposure to full sunlight bleached and killed all upper leaves, sparing a few on the lower branches. Nevertheless, this potted seedling is recovering. It is producing abundant little green buds along the main stem. LESSON: Learn what sun/shade conditions a potted seedling is grown in, and maintain that level of exposure when moving and out-planting.
ABOVE RIGHT: This seedling was in perfect condition until the deciduous canopy overhead suddenly opened to full sunlight, owing to the fall of a beetle-killed Ash tree. Notice the bleached tips of leaves on the middle layer branches, and the bare branches at the upper level, where bleached leaves have fallen away. Nonetheless, there is strong recovery: light green new growth at branch tips and 3 fresh lateral branches radiating from the leader.
Do Not Prune Away Basal Sprouts
CONNIE BARLOW advises: Do not wait too long to out-plant any germinated seeds or potted seedlings. Torreya is deep-rooted and you do not want it to become "root-bound" at the bottom of the pot. Also, Torreya naturally produces basal stems. Never prune away the basal stems. If conditions become adverse (e.g., drought), Torreya may let its main stem languish, while putting a rush of new growth into one or more of its basal stems the following year.
ABOVE LEFT: The healthy Torreya at Clinton NC shows 2 generations of basal-stem growth to the right of the main stem. The pair of 8-inch diameter basal stems support healthy leaves and reproductive cones, as does the main stem.
ABOVE RIGHT: The dry summer of 2012 stressed the 2008 plantings on the hickory slope of the Waynesville NC site. But the summer of 2013 was wet, and several of the stressed Torreyas (Johnny Appleseed" Tree at right) sprouted vigorous new basal growth.
ABOVE LEFT: Chinese media posted this photo, with this caption: "Farmers hold hands around a thousand-year old Chinese torreya tree in Zhaojia Town of Zhuji City, east of China's Zhejiang Province, Nov. 7, 2017. Zhuji City is a major producer of Chinese torreya with the total output reaching over 2,500 tons in 2016." Note: Torreya trees are highly valued in Asian countries as wood for Go and Shogi game boards. See the wikipedia entry.
The multi-stem feature of that Chinese Torreya is likely a result of many centuries of sustainable yield forestry: cutting mature stems that immediately resprout anew at the base. Each subsequent generation of growth above the same rootstock thus results in a multi-stemmed, widening cluster of trunks.
ABOVE RIGHT: The same growth pattern can be seen in COAST REDWOOD. In this photo, the logging of a huge, single-stemmed Coast Redwood in California resulted in a massive set of resprouting basals. (Photo Connie Barlow, Humboldt County, 2017)
ABOVE LEFT: In September 2004 the storm remnants of two hurricanes passed through the Biltmore Gardens in North Carolina. The grove of mature Florida Torreya trees (planted in 1939) was severely damaged when the tall over-topping canopy of White Pines were so damaged that they had to be removed. Some of the original Torreyas were toppled, too. The three remaining torreyas on the uphill side of the sidewalk had to have their tops removed by staff for safety reasons, as they were right alongside a paved road and a sidewalk.
ABOVE RIGHT: As of 2015, and typical for this genus, no new leaders are heading upward from the upper areas of the original stems. Instead, trees "F" and "G" have grown a massive amount of basal sprouts. Immediately following the storm, such basals are essential for keeping the roots alive with sufficient photosynthates, now that the basal area was suddenly open to full sun. A basal thicket will maintain before the tree makes any attempt to regrow upward. In a wild setting, such as California, home to Torreya californica, this genus will eventually preference two or three basals and grow them skyward. This new set of leaders eventually overtops the injured main stem. Over centuries, these basals may grow large enough to encircle the central area and even fuse.
Assessing the DANGER of DEER
EARLY ADVICE BY CONNIE BARLOW (later superceded; see bottom of this brown box): I am aware of no accounts of deer eating needles or stems of Torreya taxifolia. The needles are more prickly than even the prickliest spruce I have ever touched. New leaf growth is soft and not prickly, but when it emerges in the spring there are already lots of more enticing plants for deer to eat.
The real danger of deer for Torreya is buck deer using young trees to scrape the velvet off their antlers.
ABOVE LEFT: A young Douglas-fir (in Colorado) scraped by a deer.
ABOVE, TOP RIGHT: A young California Torreya (in front of moss-covered log) growing beneath a shady evergreen canopy. Torreyas that grow in shady conditions tend to take a shape that would be very attractive to deer. However, almost all the California Torreyas I visited in 5 different locations were on such steep slopes, in vast evergreen forest preserves, that no deer would likely ever visit them.
ABOVE, BOTTOM RIGHT: Like many conifers, Torreya taxifolia will grow full-to-the-ground foliage if placed in full sun. The lower branches sometimes (but not always!) protect the bark of the trunk from deer antler damage. (See more full-sun Torreyas here and here.
However, if your Torreya is situated in a shady, flat environment where deer are prevalent and especially if few other small trees attractive to bucks are nearby, then almost certainly you will need to protect it in autumn with branch piles, or fencing until it matures to a height deer will not choose to scrape. Note: 2015 a forester advised me that 3 iron T-bars pounded in a triangle configurations a short ways out from the stem will fully protect the stem and lower branches and with a lot less effort than installing a wire cage around the whole plant.
ADVICE BY FRED BESS (in Ohio): The Torreya that deer damaged here in Ohio was one of the plants in full sun and that had branches to the ground. The buck damaged several of the branches on one side of the plant and, as they are only about 3 ft. tall, I was lucky that's all he did. The Torreya that is in the shade had no issues; I have since fenced that tree in and fenced around those in the sun, too. Thus, if deer are a possible issue, strong measures need to be taken! Living in a suburb where deer are more common than rabbits is bad. I have at any given time of the year (except the dead of winter) 15-20 deer through the yard daily. I have learned to take few chances and that most repellents do not work for more than a week or so.
2020 OBSERVATIONS BY RICH LARSON AT DAWES ARBORETUM, OHIO: ... I expected deer to browse them [the torreya seedlings] and we do fence young plants in every case even though when they mature, they are resistant or rarely immune. But a recent planting has not been fenced for 2 years now and so far, no deer browse has been observed. That is only one example of course and hardly translates into declaring them as resistant as Asimina, Buxus, Berberis, Spiraea, Cryptomeria or Cephalotaxus, but it seems promising.... It appears that the species is quite resistant to deer browse, and we are not obligated to fence them as with the closely related Taxus sp.
2020 ADVICE UPDATE BY CONNIE BARLOW - Whether by deer or rodents, newly germinated seedlings may have the apical nipped, doing great damage to the new sprout, although not usually killed. The only place where "freeplanted" seeds put directly into forest soil unprotected by cages were all undamaged by any browsing was at Shoal Sanctuary in Florida. Our torreya planter in the Ocoee Watershed in TN (east of Chattanooga) had severe browsing by rodents of newly germinated seeds, but apparently no browsing by any creature of the older potted seedlings when moved into their final within-forest destinations, uncaged. CONCLUSION: Each planter needs to assess the deer population / winter hunger at their particular site. And recognize, too, that rodents may make a practice of clipping off sprouts of new germinations of any tree species that occur too close to what they regard as their home base or crucial tunnels. So an element of luck may be involved, no matter how excellent one's habitat assessment and site considerations may be.
2022 CONCLUSION BY CONNIE BARLOW: Although the tips of Torreya leaves are far pricklier than even the sharpest spruce, when new growth emerges the tips are soft and thus cannot offer any protection against herbivory.
BELOW: Notes taken by Connie Barlow in December 2007, when visiting Atlanta Botanical Garden
COLLECTING SEED: Atlanta Botanical Garden harvests about 600-700 seeds per year now from their outdoor "potted orchard" of original genotypes established in 1991 from rooted branchlets cut from the parent trees in native habitat. They are able to collect so many seeds for three reasons: First, they manage the seed trees for maximal seed production, which includes "stressing" them (not fertilizing them and having them suffer some drought). Second, they attach wire cages to surround the ripening seeds to ensure that squirrels won't beat them to the harvest! Atlanta suggests that, ideally, seeds should be collected only when they are fully ripe that is, when the seeds actually fall off the branches into the cages. Third, trees propagated from rooted branchlets begin producing cones twice as quickly as trees propagated from seed.
PREPARING SEED: Atlanta uses a knife to cut away the fleshy sarcotesta by hand if the seed is not fully ripe. If the seed is fully ripe, then the sarcotesta will be easy to remove even without a knife.
KEEPING THE SEEDS MOIST! Atlanta emphasizes the importance of keeping the seeds from drying out. If the sarcotesta has been removed, Atlanta reports that even if just a few days pass, germination rate can be reduced substantially if the bare seed has to sit in the air. If such happens, then they recommend soaking the seed(s) in water for 24 hours and then immediately planting. For shipment, surround the seeds with sphagnum moss (fungus-free orchard moss or New Zealand sphagnum) inside a ziploc bag. NOTE: Other propagators suggest that even seeds arrive so dry that they float when put in a vessel of water they still have a chance at germination if they are soaked long enough that they do sink again, but it is best to never let them get that dry.
WHEN TO PLANT SEEDS: Atlanta plants the newly harvested seeds as soon as the sarccotesta is removed. They have found that germination regularly happens in Atlanta in April or May, following the seeds' first full winter in the ground outdoors. It seems that the seeds must experience some freezing ground, and that the rigors and shifting temperatures of an outdoor winter in Atlanta work very well for their 80 to 90% percent germination rate.
WHERE TO PLANT THE SEEDS FOR GERMINATION: Atlanta Botanical Garden has limited space, so they plant the seeds for germination outdoors, right next to their building, under a full evergreen canopy, so there is little if any direct sun hitting the soil. Atlanta emphasizes the importance of having the germination soil in contact with outdoor ground, in a "forest" setting, so that mycorrhizal fungi are readily available through natural processes. Click here for a photo-essay on best practices for germinating T. taxifolia.
EXACT SPECS FOR PLANTING: Put the seed on its side and plant it in well-drained soil, with only about an inch of soil covering it. Because Atlanta keeps track of seeds and seedlings by who the mother plant was, they use plastic pots (with drainage holes at bottom) for germination, with 5 to 6 sibling seeds all planted in the same small pot (see photo).
WATERING REQUIREMENTS: The seeds must be kept moist, so in Atlanta, in full shade habitat through the winter, they water the seeds about every 5 days.
PROTECTING GERMINATING SEEDS FROM RODENTS: Because Atlanta keeps track of seed identity, they plant the seeds in plastic pots (with porous bottoms) that are then rested on the outdoor ground, so the pots protect the seeds from rodent attack from below. Soil is poured over the pots to fill in the gaps between pots on up to the pot tops. For protection from above, they constructed a wire enclosure with hinged top "doors" for human access. (See photos below). If seeds are planted for germination directly in the ground with no pot, then you must put a layer of wire mesh beneath the seeds too.
TRANSPLANTING THE GERMINATED PLANTS: By June or July the foliage of the germinated plants is beginning to touch the wire mesh canopy of the enclosure, so it is time for planting in larger pots, one individual to a pot. Certainly, for propagators who have fewer seeds to deal with and more space, you could germinate one seed to a pot and thus not have to transplant so early. By the time they transplant the newly sprouted plants, the big nutrient package in the original seed has been pretty much used up, and may have already dropped off. Again, if you are transplanting into a pot rather than the final outdoor site, then make sure the pot sits on forest soil in a real outdoor setting. (Fabulous photos of a germinating Torreya seed can be viewed at Arboretum de Villardbelle website.)
SITE CONDITIONS FOR GROWING SEEDLINGS INTO TREES: Based on their experience in the climate of Atlanta, ABG surmises that morning sun and afternoon shade is best to protect the trees from the hottest summer days. They also surmise that well-drained soils on slopes are the best places to have the plants grow. But at the botanical garden, the only site they have for their "potted orchard" and the few plants that actually get planted in real ground are flat-ground sites that get the afternoon sun instead of the morning. The potted orchard, nonetheless, has a lot of shade, positioned as the pots are are in the shade of tall oaks (see photos below).
PERIODIC LIMING: Atlanta limes their potted seedlings and older specimens maybe every 5 months or so, or whenever the tree looks like it might need it. They sprinkle some lime on top of the soil from the stem out to about "the drip line". This may be a crucial help for protecting the tree from malevolent fungi that can do damage if the soil acidity gets too high. (Click here to learn more on the importance of liming). Note: Chris Larson reports that liming brought two of her Torreya taxifolia trees at Shoal Sanctuary in northern Florida back to health (their leaves had begun to turn yellow) but were revitalized into green. Click for Larson's photo-report of liming success of T. taxifolia in northern Florida.
DON'T PRUNE AWAY THE STUMP SPROUTS: Even 3 year old seedlings will begin to grow stump sprouts from the base. Connie Barlow suggests that you never prune back the stump sprouts. If the main stem is ever lost to fire or treefall, one of those sprouts will respond by beginning to grow into a new main stem.
WHEN TO EXPECT FIRST REPRODUCTION: For female trees, Atlanta suggests that the earliest you can expect any seed reproduction from plants grown from seed is 12 years. And much later than that if you haven't done everything you can to help the tree grow and then encourage it to set seed. But you can get reproduction in maybe 4 or 5 years if you begin with cuttings! (Read more on that next.)
NOTE: Based on Connie's experience visiting the sibling species of Torreya in its wild, native habitat in California, her own supplemental recommendations are these:
STEEP SLOPES: Torreyas are superb at growing on slopes so steep you can't safely walk them. In such settings, they seem to do very well if planted right next to rocks and boulders that are themselves solidly embedded. Such rocks can also offer helpful shading of soil for moisture retention when the little seedlings are more vulnerable to drought and hot summer sun.
SLOPE ASPECT: Unless you have elevations of 5000 feet or more, I would avoid direct south-facing slopes. East or west facing slopes are probably the best.
CHOICE OF CANOPY: I would definitely plant Torreya trees under some sort of semi-open canopy. Top choice would be under tall deciduous trees, so that they have full access to winter and spring sun and can get some mottled summer sun too.
SUN IS IMPORTANT: In California, I saw some Torreyas barely surviving (spindly stems, with little if any new growth) in absolute total full shade beneath doug firs and redwoods, but obviously these are stump sprouting from ancient root stock that got its start when there was still some sunlight. Torreyas will not even try to seed if there is insufficient sun. It even seemed that each branch made its own "decision" about whether sunlight was sufficient, because I noted some trees whose only seeds appeared on the branches best exposed to sun. But in southern climates, you've got to be careful about not exposing them to too much intense sunlight in the hottest months. Note the photo below where you see Atlanta protecting its potted seedlings from too much sun by use of a black netted canopy shade.
Propagating Torreya taxifolia from ROOTED CUTTINGS
• OVERALL ADVICE FROM EARLIEST TORREYA GUARDIANS: LEE AND JACK
ADVICE FROM LEE BARNES: "It's best to collect dormant cuttings, which tend to root then put out new growth. Growing cuttings tend to put out new growth prior to rooting, so it is best to root those under mist or high humidity. As I remember, high auxin rooting compounds created lots of callus growth and not so many roots."
ADVICE FROM JACK JOHNSTON (October 2020): "Cuttings of Torreyas taken this time of year root without fancy equipment. Just a little rooting hormone, a humidity dome of a glass or plastic bottle/jar, deep shade to protect from the sun until rooted, and time. Seed production on such trees which may lack apical dominant growth is good. Seeds are easy to pick.... Rooted cuttings tend to develop good roots but no tap root so far as I know. Sometimes the cuttings root and just sit there for a period of time, and at other times they grow with vigor. Once they start growing they do well. The practical advantage of growing rooted cuttings without apical dominance is that the fruits can be reached for years, then can still be reached with a short ladder.
For massive seed production I would suggest growing cuttings and placing them in almost full sun. The sun will be hard on them when they are small, but then they adapt to handle it. This makes the bushes full and they can therefore produce a lot of seeds. I have seen plantings of cutting grown Torreyas producing seeds, and the ones in the sun are far superior.
27 September 2019: "How to pack Torreya cuttings [for mailing]: fold damp paper towel, wrap around numerous cuttings to include 2 inches of the base with the towel folded over so that the ends are covered. Secure with rubber band. Place in ziplock bag for moisture seal."
• ROOTING SUCCESS BY CLINT BANCROFT
28 SEPT 2017: Clint Bancroft reports that of 3 propagators of the branchlets cut in 2016 from the big Florida Torreya in Columbus GA, only his have rooted and stayed alive. He grew his "under domes":It appears I have had success with the Columbus, Georgia cuttings. Not 100% survived but it appears many did. Jack Johnston lost all of his portion, as did Nearly Native Nursery in Fayetteville, GA. I don't know what technique was tried in Fayetteville, but Jack tried rooting his in plastic bags. I grew mine under domes, and kept some outdoors and some indoors the first Winter. I did try a few in a sealed container (not unlike a plastic bag) and lost ALL of that bunch after they had survived the Winter (these were kept indoors in an unheated room) and had even put on new growth in Spring, but then all turned brown within days of each other and suffered what we (in Anesthesia) used to call "severe death". So maybe trying to root them in sealed containers is not a good option. It appears so.11 OCTOBER 2017: Clint Bancroft reports:I previously wrote you about Jack Johnston's having lost all of his cuttings from the Torreya in Columbus, GA. Jack had put his cuttings in pots sealed in zip lock bags. I, on the other hand, appear to have had success with all the Columbus tree cuttings that I kept under domes (cloches). I lost all of the ones I put into pots, using the same medium as the ones under domes, and putting the pots into a sealed plastic storage box (essentially like a zip lock bag).UPDATE 20 FEBRUARY 2018: Clint Bancroft reports:
I told you that Jim, at Nearly Native Nursery in Fayetteville, GA, had also received Columbus cuttings from us. I knew from Jack Johnston that all Jim's cuttings had died, but at the time I wrote you I did not know how Jim had handled his cuttings. Today I saw him for the first time since we gave him the cuttings last November. I asked him how he had handled his Columbus cuttings and he said, "I followed Jack's lead and put them in zip lock bags!" Of course this proves nothing (or does it?) but it seems that rooting cuttings in sealed bags (or sealed plastic storage boxes in my case) yields negative results. My guess is that while the cutting itself needs continual high humidity, the soil needs exposure to fresh air. Using the dome technique the soil around the dome is exposed to ambient air whereas with the sealed techniques the soil is not exposed to fresh air or movement of air. I tried rooting a bunch of round leaf birch cuttings this summer and used zip lock bags since I was out of domes. I lost every single cutting.The original Columbus cuttings are rooted and Jack Johnston said "they look fabulous". I have made 2 more trips through Columbus and took more cuttings in Dec. 2017 and Feb. 2018. The big tree there still looks healthy in spite of its many scars.UPDATE 16 SEPTEMBER 2019: Clint Bancroft reports:
"The 16 apicals I got from my last Columbus trip seem to be doing very well. And as we learned from the Highlands apical cutttings, they continue to grow with radial symmetry!"
• ROOTING SUCCESS BY FRED BESS (Ohio)
MAY 2021: the PHOTO BELOW shows the results of my attempt to root T. tax cuttings. I started this cutting project December 2019, when I collected 25+ cuttings from the Spring Grove Cemetery tree in Cincinnati.
I followed the guidelines on the Propagation page. Pictured here are the cuttings that worked.
• HOW TO ACHIEVE VERTICAL TREE-LIKE FORM FROM CUTTINGS
BACKGROUND: December 2016, Connie Barlow asked Torreya Guardian leaders for their suggested best practices for counteracting the usual "plagiotropic" growth pattern (horizontal, jumbled growth) that occurs when a cutting from a horizontal branch of a Torreya is successfully rooted. She wrote:Florida Torreya propagation has benefitted tremendously from the fact that a branchlet cut from a lateral branch of a mature tree thinks it is still a lateral branch on a mature tree even after it is successfully rooted and planted out. That's how the Atlanta Botanical Garden got seed production in just 7 years after clipping branchlets in the early 90s from all the remaining specimens in the wild of n. Florida. You can see photos of their operation here.
Also, Jack has seen the now 20+ year old clones in their outplanted sites (Visitor Center Trail at Smithgall Woods, GA) and they are still shrubby easy for squirrels to pluck seeds from (whereas on tall mature trees all the seeds are so far out on the tips that the squirrels can't get to the ends to nip them off, so the seeds drop to the groud on their own schedule). Fred Bess in Cleveland (TheBotanyGeek) has been nurturing a rooted-branchlet Torreya shrub for almost 10 years. See the shrub and watch him talk about it in the first 90 seconds of this video I made of his project in 2014.
Dec 12, 2016 email from JEFF MORRIS (Torreya Guardian in Spencer, NC): "The method used in the greenhouse that worked for me was to stake it with a metal tree stake for the season, and when there was no doubt as to the health of the root system, I carefully transplanted it [and the stake] into a new pot. Two seasons of this, and I achieved an upright growth for two T. taxifolias. A third tree was not predisposed to this type of transplanting due to advanced growth of the root system that would have resulted in damage. But if it's less than 4 years since rooted, you'll probably have some success."
January 2017 email from FRED BESS (Torreya Guardian in Cleveland, OH). Fred visited the old Torreya taxifolia in Spring Grove Cemetery, north of Cincinnati OH. He confirmed that this tree has never developed an apical (vertical) single or double stem. Rather, it is still a multi-stemmed "shrub", indicative that it was nurtured from a rooted branchlet cutting. See Fred's photos of that shrubby old Ohio Torreya.
WHAT WE HAVE LEARNED :
BEST TO USE APICAL CUTTINGS FROM BASAL SPROUTS IN ORDER TO ENSURE A TREE-LIKE FORM. The online list of actions included in the official recovery plan (USF&WS) confirms that rooting cuttings from vertical "leaders" (such as those found on basal sprouts) is necessary for nurturing a tree-like v. a shrub-like growth form: "The ABG has switched [from propagating cuttings from lateral branchlets] to propagating cuttings made from 'leaders' (the rapidly growing apex of a tree). This process forms upright plants of about two-feet tall in about two years." See the 17th column ("Comments") of the 11th row (action #322) at Recovery Plan ad hoc Report Results.
Torreya's close relative, Cephalotaxus, is documented as producing tree-like form from its "terminal cuttings" (which comports with our own suggestion of using the apex of a basal sprout):"Informal observations in the eastern United States indicate that terminal cuttings are slower to root than lateral ones, sometimes needing an additional two to four weeks; these will, however, result in plants with upright growth. Lateral cuttings, while quicker to root, result in plants with prostrate growth, at least for a number of years.... The only challenge in propagating this genus is the degree of patience required. it would be worth experimenting with fog systems to see if they might hasten the process of rooting."• Proof that cutting of basal leader tip yields tree-form Torreya
Source: Cephalotaxus: The Plum Yews, by Kim E. Tripp, 1995, Arnoldia.
April 2019 email from CLINT BANCROFT (Torreya planter in Ocoee watershed of Tennessee) to Connie Barlow:"Look at the new growth on this cutting from Highlands, NC! The cutting is the apical tip from a basal of one of the mature trees."Photo left, by Clint Bancroft, is April 2019 of a rooted cutting (collected October 2017; see 11 October 2017 entry above) that displays superb vertical growth. Photo right is by Connie Barlow 2006, during a Torreya Guardians site visit to the near-century old Highlands NC Torreya grove. Notice the prolific basal sprouting, of various ages.
March 2020 CLINT BANCROFT writes:
Here is the apical cutting [just removed from its pot] that put on four laterals last year. [See photo immediately above left.]
Look at the roots she developed! It currently has a central bud ready to go this spring, but no [second tier of] lateral buds at this time.
Although I was very pleasantly surprised by the root development, I don't know if this is typical or exceptional root formation since this is the first rooted cutting I have removed from its rooting pot.
I am not sure exactly what rooting medium I used but it was largely soil after 2+ years in the pot. The original soil was probably from my yard in Atlanta, mixed with the "soil conditioner" sold by Lowes. That soil was a rich loam which I had heavily amended with leaves over the 26 years I owned the property. There was probably a hefty admixture of the "soil conditioner" to begin with but it had mostly degraded over the 2 plus years it was in the pot.
Although I was very pleasantly surprised by the root development, I don't know if this is typical or exceptional root formation, since this is the first rooted cutting I have removed from its rooting pot. I will be certain to label it as CUTTING GROWN so that we can learn if a cutting grown apical will eventually form basal sprouts.
CLINT BANCROFT wrote 5 January 2021: "I contacted the owner of the Columbus tree again and he allowed me to come take more cuttings in November. The last ones I took in 2018 have rooted. I hope they will put on some radial growth this year. They are all apicals. I quit trying lateral cuttings unless that is the only option. I still have the original 2016 lateral cuttings Jack and I collected from Columbus. They are clearly rooted but four years later they still have produced no new growth."
Editor's note: When outplanting potted specimens (whether seed or cutting-grown), make sure the soil used in the pot is either (a) shook off the roots before planting or (b) is not significantly flufflier than the forest surrounds as fluffy soil will encourage burrowing rodents and thus destroy torreya roots. Read this crucial section of this webpage: Beware of Rodents!.
LEARNING: The original cuttings of wild specimens in the Florida panhandle were collected three decades ago from branches that necessarily assume shrubby growth forms. Wild stock was so weak that cutting of basal terminals would not have been appropriate. However, when collecting vegetative growth from healthy horticultural plantings in northward states, we now know that apical growth of basals are essential for ultimately producing tree forms.
* * * * *
Overall recommendations from the official team that rooted 2,622 branchlet cuttings from 166 wild Torreya trees in the early 1990s
METHODS: The methods here are excerpted from a July 1998 paper that appeared in Public Garden: "The Ex Situ Conservation of Stinking Cedar". Among the 4 authors were Ron Determann of the Atlanta Botanical Garden and Rob Nicholson of the Botanic Garden at Smith College (Massachusetts)
Previous trials with Torreya cuttings (Nicholson, 1987) had experimented with various rooting hormones and hormone strengths and had produced a topmost rooting percentage of 65%. In an attempt to increase this percentage, different rooting media were compared and the hormone strength was doubled from 5000 ppm Indolebutyric Acid (IBA) to 10,000 ppm IBA in 50% EtOH. A total of 666 cuttings from 45 different genotypes had the bottom 4 cm of needles removed from the stems, were given a fresh cut, and the basal portions were immersed in the 10,000 ppm IBA solution for five seconds. These were then stuck under a poly tent in a medium of coarse builder's sand and medium grade perlite (1:1 by volume) with a bottom heat of 75 degrees F. One thousand eight hundred and forty- eight cuttings from 121 different genotypes were treated in the same manner, but a rooting medium of #10 grade crushed pumice, shredded peat moss, and medium grade perlite (6:2:1 by volume) was used. Cuttings were evaluated after six months and potted on. Rooting percentage of those cuttings stuck in the sand/perlite medium was 79.2 percent while those cuttings stuck in the pumice/peat/perlite mix rooted at a percentage of 90.8 percent.
The cuttings rooted in the sand/perlite mix produced an average of 2.90 main roots and 3.44 total root tips. The longest root length averaged 6.37 cm with an aggregate root length averaging 12.98 cm. Highest values recorded for each category were 13 primary roots, 13 total root tips, 14 cm greatest length, and 42 cm aggregate length. The cuttings rooted in the pumice mix produced an average of 2.40 primary roots per cutting and 5.09 total root tips. The longest root averaged 10.26 cm with an aggregate length averaging 16.92 cm. Highest values recorded for each category were 10 primary roots, 18 total root tips, 22 cm greatest length, and 49 cm. aggregate length.
A comparison of these two media showed that the pumice mix yielded a higher percentage of rooted cuttings, and a more highly branched root system of greater total length. Cuttings were potted and grown for two years and then shipped to botanic gardens and biological institutions worldwide for observation and research. Institutions receiving plants were the Arnold Arboretum of Harvard University; Bok Tower Gardens; Royal Botanic Garden, Edinburgh; Illinois Natural History Survey; Mercer Arboretum; North Carolina Botanic Garden; Tall Timbers Research Station; USDA Forest Service, Berkeley; and USDA Forest Service, Gulfport.
Of particular note is the collaboration between The Botanic Garden of Smith College and the Atlanta Botanical Garden. Cuttings sent to the Atlanta Botanical Garden were raised in containers and by 1997 some had grown to five feet and had begun to set seed. A nursery mix of 15 parts composted pine bark mulch, one part granitic sand, and amendments of lime, bone meal, and cow manure proved to be an excellent growing medium, and the plants were grown outside under 50 percent shade. Fertilization was provided by high nitrogen 17-6-12 Osmocote, applied at half strength twice a year. If the plants looked peaked, additional fertilization was by 20-10-20 liquid feed.
All plants were labeled as to original locale. In 1997 these plants were the source of additional cutting material. More than 4,000 cuttings representing 150 genotypes were installed at The Botanic Garden of Smith College. Once rooted, these will be transported to the Atlanta Botanical Garden where a distribution to other botanic gardens, agricultural stations, colleges, nature reserves, and state parks in Georgia is envisioned.
UPDATE: Direct email communication from Rob Nicholson, Smith College, February 2015: "I think you want to [cut branchlets] in the fall, as if you try later, the cuttings will break bud and be trying to make roots and shoots at the same time. Not ideal."
* * * * *
Notes taken by Connie Barlow in December 2007
While visiting Atlanta Botanical Garden)
ADVANTAGES OF BEGINNING FROM CUTTINGS: There are two major advantages of growing this endangered tree from cuttings rather than from seed: (1) You can begin to harvest seeds in 4 to 5 years from specimens begun as rooted cuttings, rather than the usual 12 to 20 years for trees grown from seed. (In fact, if you choose a branchlet that has already begun to cone, you will need to remove the cones from the rooted cutting until it is big enough to support the energy demands of coning.) (2) It is a lot easier to obtain cuttings than it is to obtain seeds of this highly endangered species.
DISADVANTAGES OF BEGINNING FROM CUTTINGS: As with the ginkgo tree (which is usually rooted from branch cuttings of trees old enough to be sure they are male and will thus not produce smelly seeds), the growth form of a tree begun from a horizontal branch will be weird). See the photos below of the trees grown from 1991 rooted branchlets at Atlanta Botanical Garden: instead of a vertically trending main stem, the trees tend to lean and branch out more like a bushy yew. Also, while seed-grown trees will produce suckers at the base of the trunk, specimens grown from cuttings never will. This puts them at heightened risk of dying if something bad happens to the main stem (e.g. a tree falls onto the main stem, breaking it; or a drought causes dieback of many of the branches of the main stem.) A number of Torreya growers have been surprised to see a presumed-dead tree restart and look healthy all because of a basal stem or bud taking over and starting again.
BEGINNING WITH VERTICAL STUMP SPROUTS (SUCKERS): If you begin with cuttings drawn from the vertically-trending stump sprouts found at the base of many specimens, then you will get a real tree-like form as a result. The disadvantage, of course, is that the onset of coning will be later.
HOW TO NURTURE A CUTTING: Atlanta Botanical Garden has great success in rooting many gymnosperms from branch cuttings, including Torreya taxifolia. In July 2007, Atlanta Botanical Garden decided to "back up" the precious original genotypes represented in their "potted orchard" (itself begun from branch cuttings from wild individuals in 1991) by rooting branch cuttings from each original genotype. By the time I visited ABG in December 2007, those cuttings had successfully rooted and had been transplanted into bigger pots and placed on the ground outdoors to ensure contact with micorrhizal fungi. ABG staff took me on a tour of their "misting room" (see photo below) and showed me examples of other gymnosperm branch cuttings in the process of being rooted. The cutting is scored with a knife in several places near the cut end; the end is dipped in growth hormone (3,000 to 5,000 ppm solution); no fungicide is used. The cutting is placed in a little pot in which a combination of pumice, perlite, and milled (ground-up) sphagnum moss entails the "soil" matrix. (Potting soil is only used after the roots have grown and the cutting is ready for transplanting). Note: You can acquire a supply of tiny pumice particles at a horse-stable supply company. * * * * *
Recommendations by Jack Johnston, based on his experience
propagating branchlets and seeds at his home in northern Georgia
... A bit more about how Torreya can be rooted: The key is to keep the cuttings at 70 degrees F., but the air temp. can be cooler. A heated rooting bed is used for this. A watertight "bench" maybe 6 inches deep is lined with plastic to make sure it holds water. A one-inch layer of perlite is next. Then a heating cable covered with hardware cloth 1/2 inch squares holds the cable down. The bench has about three to four inches of coarse sand and perlite mix on top of the hardware cloth. The mix is kept moist.
Cuttings are stuck after frost. A wire "canopy" well above the cuttings is used to support a plastic drape. In a greenhouse the plastic is covered with shade cloth. The plastic drape is lifted once a week all winter to check for moisture in the sand/perlite and to add a little water if needed. Dead cuttings are removed. Growth should be well along by April. This system can be used in a basement with a grow light suspended over the cuttings.
Cuttings taken in Nov. 2009 after frost were placed in a closed plastic container purchased at Walmart. Cuttings were about 3 to 4 inches long. The container was partially filled with a mixture of perlite and peat 50:50, watered, cuttings dipped in 0.8% hormone and stuck in rooting media. The lid was snapped on the plastic container to prevent moisture loss. The container was stored near a basement window at 70 degrees. No additional watering was needed as the cuttings rooted. Rooting was in progress when the cuttings were checked 8 weeks later. It remains to be seen how well the cuttings will grow.
Note: Seeds in an outside seed bed were checked. Voles were able to reach some seeds by digging under the wire-mesh-protected bed, and ate through the thin shells of the seeds much like a squirrel chewing into a nut. Remaining seeds were relocated to a vole-proof environment.
2011 Note by Jack Johnston: "Two years ago I had seeds and planted them outside in Dec. in one gallon pots with many slits down the sides. Drainage was good. Germination occurred the first and second spring. I have found that using pots is easier than dealing with voles that get in seed beds. Germination was excellent using pots. After seedlings were a few inches high, they were moved into individual pots."
LEFT: July 2008 photo of the protected outdoor bed where Jack planted in autumn 2007 T. taxifolia seeds he acquired. Notice the conifer-shape sprouts growing up through the mesh. Jack reported in January 2010 on the progress of these seedlings: "Seedlings growing outside in the ground (from seeds harvested and planted in autumn of 2007) have reached a maximum of 9 inches after two years growth. Lime has been applied twice a year."
Note: Subsequently Jack has planted seeds in pots enclosed in a tight wire mesh "box" outdoors to forestall rodent predation. He also learned by experience that the perlite must be shaken out of rooted branchlets of Torreya before planting out into the yard. Click for September 2010 site visit captioned photos of Jack Johnston's methods of germinating, rooting and outplanting Torreya taxifolia.
Nov. 2016 Note by Jack Johnston on method for ROOTING BRANCH CUTTINGS outside, using 1-gallon ziplock bags (in late August):Torreya cuttings are the growth for the current year. Needles are stripped off the bottom 1.5 inches of the cut branchlet. Nick the bottom of cuttings to increase rooting surface area. Two 3-inch pots fit nicely inside a one gallon ziplock. Fill those pots with Nature's Helper or finely ground pine bark, mixed with granite grit or perlite. Thoroughly wet the mix before sticking the cuttings into it.
Use Hormodin 3 rooting powder (or any rooting hormone). Use wooden skewers (grocery store is the source) to stick in the pots to keep plastic off the cuttings; (the Sticks have to be shortened a bit to fit).
Once cuttings are stuck, seal the 2 pots in one ziplock bag and place it out of the sun. Under shrubbery could work; I used an open carport.
It is not necessary to water the cuttings for the next 8 weeks; by then, they should be rooted. Transplant into a larger pot for the winter. There should be no growth at tips at this time. With a greenhouse and bottom heat, cuttings can be rooted in cold weather.
August 2016 Note by Jack Johnston: "Online if a Google search is done for "air propagator" one sees a plastic clamshell that can be attached to a branch. The shell is filled with peat plus crystals that hold water. I have used this method for other species, and think it would work on Torreya. A trial kit was available through a supplier at Huntsville, Alabama. Worth a try I would say."
July 2016 Note by Jack Johnston: "It is my opinion that cutting-grown plagiotropic plants should be grown for seeds. The seeds on plagiotropic shrubby growth can easily be reached to pick. Full sun, of course, is recommended. Growing them in the middle of a 50-acre field well away from squirrels would be ideal. I think that these cutting-grown trees may produce quicker than seedlings can.
RECOMMENDATIONS FROM ARBORETUM DE VILLARDBELLE (2010):"From my experience with Torreya californica, the seeds will germinate whatever the temperature or the chilling period or even no chilling period at all. I had seeds germinating while kept all the time in the refrigerator or all the time at room temperature. The most important factor as noted in previous messages is to keep the seeds moist.
The main question is to know whether the seeds are fertile or not. It often happens with young trees that the pollination rate is not yet what it will become with mature trees. My experience with Torreya californica shows a germination rate of 70%. Of course local meteorological conditions at pollination time play an important role.
Rather than trying to root cuttings, I would suggest GRAFTING T. taxifolia onto T. californica. The problem with these kinds of propagation methods is that from what I could see in Europe so far the plants will remain shrublike spreading horizontally with no true leader."
• Fabulous photos of a germinating Torreya seed at Arboretum de Villardbelle website.