Germinating, Planting, and Nurturing Torreya taxifolia
GERMINATING from SEEDS (detailed advice)
Beware of RODENTS (all Torreya planters please read!)
ABILITY TO RECOVER from herbivory
Beware of SNAILS during germination
Planting seedlings orchard style
Planting seeds directly into WILD FOREST ("Free-planting")
Choose habitats based on INDICATOR SPECIES
Advantages of Planting Next to ROTTING HEMLOCK TREES
SHADE or SUN?
SCARIFY SEEDS for faster germination?
Do Not Prune Away Basal Sprouts
Encouraging SYMBIOTIC MYCORRHIZAL FUNGI
Assessing the DANGER of DEER
Monitoring and Reporting Results
ACHIEVING VERTICAL GROWTH from BRANCH CUTTINGS
How Far NORTH Will "Florida" Torreya Grow?
Photos of SPROUTING SEEDS at Arboretum de Villardbelle
Endangered Species Propagation of Torreya at Atlanta Botanical Garden
Importance of LIMING in Florida
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.
GERMINATING Torreya taxifolia from SEED
BE PATIENT: highly variable germination time. (Most seeds require 2 winters.) If you overwinter them in your fridge, wrap their bag in a towel to ensure NO LIGHT GETS IN.(Conifer seeds can sense light; on-off artificial light can confuse them; because they will grow up toward the light, do not keep jostling germinating seeds prior to potting or free-planting them.)
• 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 Guardains.
Torreya Guardians experience has ranged from 6 months to 4 years for seeds to germinate.
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 this far. 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.
Watch a 13-minute VIDEO: "Germinating Torreya Seeds: 2015 report".
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.
Photo by Fred Bess, February 2016
(Torreya Guardian near Cleveland, OH)
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].
"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 notes 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.
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.
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?
Photo left: April 2012 Connie 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, rodents got them all, so the experiment was quashed.
Lamar Marshall mechanically scarred all his seeds from the 2013 harvest with a hacksaw (Connie 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.
2011 Advice from Jack Johnston:
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.
2016 Advice from Court Lewis:
Court Lewis (TN) received his first set of seeds in November 2015. He decided to use the can technique suggested by Jack Johnston (above).
Photos LEFT by Court show his final stages of planting. Read his detailed methodology (with more photos) here in PDF. He planted 2 seeds per can one scarified and the other not. His results will help us evaluate the benefits of scarification.
30 seeds were planted in this fashion, 2 per can. "Five additional seeds are planted without cans but 5 inches deep, well below the frost zone, so it will be interesting if they show different results from the other 30 (and whether rodents can detect them at that depth)."
2012 Advice from Lee Barnes:
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."
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 when "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.
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.
Jim Thomson, Torreya Guardian in Cullowhee NC, ensures that multiple seeds germinated in the same pot do not entangle roots.
PHOTOS LEFT show the foam-board dividers he uses 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.
"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.
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 in March 2018: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. Immediately, the seeds are sent/delivered to the recipient, who in turn immediately buries the seeds into their ultimate destination placements deep enough (4 to 6 inches) or otherwise protected from rodent predation by wire cages or top-rocks. All this is 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 "freeplanting" 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!).
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.
2015 EDUCATIONAL VIDEOS for germinating and planting FL Torreya
10A: FL Torreya to North Carolina (pt. 1): 2015 report, Waynesville
First video-documentation of fate of historic 2008 rewilding action of the endangered Torreya taxifolia from Florida to North Carolina. Connie Barlow films and narrates a survey of the 21 plants in wild forest on the slope of Eaglenest Mountain, near Waynesville. Most important results are both positive and negative, which help us ascertain the habitat preferences of this species (moisture, shade, slope, aspect).
Rule of thumb: habitats with mesic, moisture-loving plants nearby (hydrangea, trillium) are a sign that torreya would likely do well there.
10B: FL Torreya to North Carolina (pt 2): 2015 report, Junaluska
Second half of video series above. Key findings: (1) Counting vegetative buds at the tips of branches misleads, as older plants sprout branchlets on older regions of branches, too. (2) Don't plant near rhododendrons that will encroach on our plants. (3) Seedlings too long in the pot (rootbound) are inferior specimens for assessing Torreya's ability to thrive in wild settings, as their roots cannot support the tree unwatered; thus the main stem may die while growth is directed to a basal sprout. (4) Full sun may be stressful for Torreya outside of watered areas, but because potted seedlings have a full-sun growth form, the plant will need to reorient branching to a horizontal, yewlike form when under a deciduous canopy in wild settings.
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. Unprotected plantings (away from logs, which are rodent habits) are underway. The video closes with a list of trees and shrubs that harbor the same root symbionts as Torreya needs, and a cautionary note about protecting juvenile plants from antler-rubbing bucks.
15b: Germinating Torreya Seeds: 2015 report
Jim Thomson, Lee Barnes, and Connie Barlow discuss what we all have learned thus far about how to germinate Florida Torreya seeds outdoors, in locales far north of the "historically native range". A lot is still unknown. But we do know that seeds harvested from the same tree in the same year will span a number of years to germinate, even when planted under the same conditions. The final 5 minutes of the video are of Connie late June 2015, showing the varied germination rates of 4 seeds she is watching closely in a rodent-protected container in Michigan.
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.
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!
Encouraging Symbiotic Mycorrhizal Fungi
LEFT: Genus Glomus is the mycorrhizal fungal partner of Torreya taxifolia. It does not form above-ground mushrooms.
A 1989 paper indicates that a relative of Torreya, Canadian yew (Taxus canadensis), has endomycorrhizae (penetrating the root cells): "Whereas Taxus canadensis (Taxaceae) was heavily colonized by VA endomycorrhizae during the entire growth season, nearby trees of Tsuga canadensis (Pinaceae) [Eastern Hemlock] were ectomycorrhizal." Note: The propagules of endomycorrhizae, unlike ectomycorrhizae, apparently are not air-borne.
March 2015 update: Smithsonian plant molecular ecologist Melissa McCormick tells Torreya Guardians (publication pending) that Torreya taxifolia associates with arbuscular (endo-) mycorrhizal fungi: genus Glomus. She reports,"Mycorrhizal fungi are likely good for the trees, as long as the trees can get enough light. If Torreya is in deep shade it won't have enough carbon to support the Glomus. As I noted in my abstract, there is also the concern that mycorrhizal colonization was lower in diseased trees simply because they couldn't support the fungi. There could still be plenty of Glomus in the soil nearby."McCormick advises, "Glomus are very widespread fungi, and planting Torreya in habitats with appropriate host trees would likely be a good way to ensure that the fungi they need are present." Here is a comparison of common tree species with which Glomus does (YES) and does not (NO) associate:
Editor's UPDATE: In 2016 a paper was published in Science that requires an immense worldview shift in how we study and interpret forestry results. "Belowground carbon trade among tall trees in a temperate forest", by Tamir Klein et al. (2 pages), is a must-read for all Torreya planters. Planting Torreya seeds or seedlings beneath a mature deciduous canopy will ensure drought and winter-wind protection, while offering opportunities for the young trees to receive sugars from the canopy via fungal root connections so long as canopy trees include those using ENDO (not ECTO) mycorrhizal types. To learn about this amazing discovery via video format, watch this 15-minute TED talk by forester Suzanne Simard in 2016: "How Trees Talk to Each Other".YES: maples (all species), tuliptree and other magnolias, sweetgum, blackcherry, buckeye, dogwood, robinia, nyssa, hawthorn, holly, hydrangea, persimmon, redbud, silver bell, sourwood, walnut, viburnum, yew, (possibly juniper)USF&WS offers this brief Report on mycorrhizal Torreya studies (scroll down the "Comments" column to find it):
NO: most conifers (incl. hemlock and white pine), beech, oaks, hickories, basswood, birch
There are, of course, other Glomus associates in wild forests of the eastern USA. See the list of VA Endomycorrhizal (VAM) Trees and Plants for other potentially helpful neighbors that may offer symbionts in their surrounding soil that Torreya would appreciate.
Dr. Melissa McCormick (Smithsonian Environmental Research Center) proposed to investigate the type of mycorrhizal association formed by T. taxifolia, identify the fungi forming the association, and quantify the degree of colonization. Dr. Melissa McCormick found no evidence that native Torreya habitats were deficient in species of mycorrhizal fungi. She found that Torreya forms associations primarily with fungi in the genus Glomus, which are known to have a role in protecting host trees against root pathogens. Torreya in native habitats had lower mycorrhizal colonization compared to Torreya planted in both forest and garden locations. This might mean that trees in native locations were less well protected against pathogens than in other locations. Alternatively, it might be that the diseased trees in native habitats are less able to pay the carbon cost of supporting mycorrhizal fungi.The arbuscular form of plant-fungus symbiosis is ancient. The Journal of Experimental Botany reports in 2008:Arbuscular mycorrhiza is the most ancient and widespread form. Paleobotanical and molecular sequence data suggest that the first land plants formed associations with Glomalean fungi from the Glomeromycota about 460 million years ago (Redecker et al., 2000). This is estimated to be some 300 to 400 million years before the appearance of root nodule symbioses with nitrogen-fixing bacteria. Arbuscular mycorrhizal (AM) symbioses can be formed with a very wide range of plant species, as many as 250,000.
• Access an excellent introduction to arbuscular mychorrizae (in pdf). Key paras:ARBUSCULAR MYCHORRIZAE ARE ANCIENT: Ectomycorrhizas, orchidaceous mycorrhizas and ericaceous mycorrhizas are all evolutionary latecomers to the root symbiotic world. In fact the most ancient, and certainly the most common, type of mycorrhiza is the arbuscular mycorrhiza, normally abbreviated as AM (formerly also referred to as the vesicular arbuscular mycorrhiza, or vAM). Their causal fungi, presently all thought to be mycorrhizal symbionts, are even known from the Rhynie chert fossils of 407-411 million years before present: some time before roots had evolved (Dotzler et al., 2009). It is often said that more than 80 per cent of plants form this kind of mycorrhiza, though Brundrett (2009), in a detailed analysis, gives an estimate of just over 67 per cent that are likely to possess mycorrhizas of this type. Just under 10 per cent are non-mycorrhizal, and the remainder form other kinds of mycorrhizas. Nevertheless, it is clear that the arbuscular mycorrhizal state is more or less a norm for plants in terrestrial ecosystems... The external mycelium ramifies through the soil, creating a network that may even connect to other host plants, producing what has been described as a 'wood wide web' (Helgason et al., 1998), though AMF are certainly not con ned to woodlands, and are amongst the most common fungi in most soils.
ROLE OF AM FUNGI: The fungi, most of which cannot grow saprobically (that is, they cannot obtain carbon directly through breakdown of organic matter), obtain their carbohydrates from the plant host. The main benefit to the hosts is in nutrient uptake, especially in the supply of phosphorous, which is absorbed in the form of poorly mobile but essential phosphate compounds. The fungi are able to access phosphate more readily, largely because of their ability to produce large amounts of exploratory mycelium in the soil. The fine threads of mycelium thus bypass the P-depletion zone that forms around roots. The phosphate is then passed on to the host plant in exchange for carbohydrates. There are considered to be other benefits to the plant such as enhancement of drought tolerance, and possible increase in resistance against root pathogens, but these are less well documented than the nutrient advantages.
Lamar Marshall uses Bio-Tone Starter Plus to ensure that his mixture of top soil, sterile potting soil, leaf litter, and a pinch of lime will offer the torreya seedling any of the mychorrizal fungal symbionts that it coevolved to associate with.
Lamar's terrier dog, Scout, does a fine job of chasing away the squirrels and eating the voles. (Photo right is Scout looking out upon the full-sun planting of Torreyas. He gives a distinctive bark at rodents, signifying that he needs to be let out to do his job.
JEFF MORRIS (2013) advises: If planted beside hemlock or other conifer (Pinaceae) rotting stump, between the roots spreading off from the trunk, the T. taxifolia seedling can take advantage of similar nitrogen-fixing bacteria that live in loose associations with roots of the same Pinaceae family of trees. Nitrogen loss would not be an issue, as these bacteria are known as 'associative' nitrogen fixers, which grow on the surface of roots.
When I was transplanting the six seedlings that Connie gave me in November 2013 [dug up from beneath the parent tree in Clinton NC], I made an observation of the Torreya taxifolia that I had not paid attention to before: mycorrhizal root nodules, similar to those I have seen on Cephalotaxus and Podocarpus seedlings in the past.
Mycorrhizal root nodules work to facilitate a plant-fungal symbiotic interaction that is vital to the health of the tree. It could also be useful in assisted migration of T. taxifolia, as we seek answers to the 'ideal' place to plant the seedlings, so that they have the best advantages available to gain necessary nutrients from the soil and atmosphere which is about 80% nitrogen, but is not readily absorbed in usable form by trees without bacterial or mycorrhizal chemical reactions. This is another reason that I believe planting the T. taxifolia between the sprawling roots beside a Pinaceae stump will lead to greater survival of northern winters in climates colder than a zone 6.
I would also speculate that an area of the forest bed where unique flora grow that require high amounts of leaf mold (a variety of fungi that assist the mycorhizzal nodules of T. taxifolia in providing nutrients to foster rapid growth of the saplings) may be more conducive to the long-term health of our plantings. Such flora may include ferns, Hepatica, Running Cedar (Lycopodium digitatum), and other moss and clubmosses. I researched this theory, and discovered that Running Cedar is commonly found among Red Maple, Virginia Pine, Eastern White Pine, Loblolly Pine, Silver Maple, and Black Cherry. Those varieties are common in the very areas the Torreya Guardians are seeking to naturalize Torreya taxifolia.
Again, these are hypotheses only. But if we can pinpoint the neighboring flora that might increase the viability of T. taxifolia, our chances of survival to reproductive maturity will increase, over those seedlings that are merely planted in a field adjacent to a forest. I would love to see the forest bed of the Torreya Californica saplings that thrive in intense shade. If my hypothesis is going somewhere, I would expect to see ferns and clubmosses alongside the saplings, to compensate for the reduced sunlight and drier conditions of the canyons that form a plurality of their native California habitat. It only makes sense that the need for energy, which the tree in an open field gets from the Sun, is found in a variety of other means when the tree is to survive in a sunlight-suppressed area.
Visit Jeff's ongoing photo-illustrated webpage of his Torreya propagation work.
2019 UPDATE BY CONNIE BARLOW: Visit a subsection of the Torreya Guardians webpage "Free-Planting Torreya Seeds Directly into Forest Habitats." Click for direct link to the subsection, Summary of Learnings 6: Siting to Maximize Mycorrhizal Connections.
Advantages of Planting Next to Rotting Hemlock Trees
PHOTOS ABOVE: The non-native woolly adelgid insect is destroying the hemlock evergreen trees of eastern North America. The map at right shows the areas already invaded and the adjacent areas of hemlock native range that will be invaded in the near future. Might the eastern Torreya species fulfill the ecological niche of moist-soil tall conifer in the wake of the woolly adelgid?
JEFF MORRIS advises that planting Torreya alongside dead and rotting hemlock stumps (or other conifer tree species of family Pinaceae) might be ideal soilconditions for Torreya. "My theory on planting adjacent to the stump of an already decaying Pinaceae tree is based upon observation and experience, for the following reasons:(1) The Torreya genus is itself a resinous tree and seems to thrive in soil next to another decaying resinous Pinaceae tree.JEFF MORRIS: The root system will grow as close as it 'needs' to by natural selection in the following manner: If roots dig in to an area that is too nitrogen-rich for the T. taxifolia, the ends of those roots will wither, but the main shoot of the root will spread into less nitrogen-rich areas. As the T. taxifolia grows and needs more nitrogen, the roots will again grow closer to the decaying source of nutrients, for as many years as it takes for the pine stump to decay. The roots on the other sides of the T. taxifolia will do the same into the poorer nutrient soil, including the surface strata where the leaf mold (or pine needle mold) provides a lesser source of nutrients.
(2) Resinous pine family trees' root systems have some common means of breaking down the fungi that deliver nutrients to the upper parts of the tree.
(3) A rotting Pinaceae stump will maintain a necessary level of moisture among the decaying roots, which will assist the T. taxifolia through the following summer's drier weather.
(4) It is a fact that decaying tree stumps emit heat, which is useful to the T. taxifolia in the winter months in assisting the development of root growth, and in colder climates for maintaining the T. taxifolia root system at temperatures which would be more characteristic of warmer USDA climate zones, thereby increasing the survival rate of T. taxifolia in zone 6 and possibly as cold as climate zone 5.
(5) If in a climate zone colder than 6, pine straw winter mulching to nearly the top of the sapling will also assist in the survival and establishment of the root system over the winter. But make certain to remove the pine straw in the Spring from the base of the sapling, and spread it around a broader area of the root spread, for greater drought tolerance in the coming months.
I have learned never to fertilize a T. taxifolia with store-bought fertilizers, but spreading the compost mixture around the base of a sapling in Spring will enhance nutrients, and the vermiculture of the worms will allow healthy fungus production that also helps the roots below. The worms dig into the soil to aerate it for better root production. I have found red wigglers originally purchased four years ago at a bait & tackle shop to be most effective in this zone 7 climate [of central North Carolina]. But other rewilders would be well advised to make their own selection based on the climate zone they are in, and the availability of worms that will tolerate their winters [and also ensuring that native worm species are used]. In some northerly forests, particularly where maples grow, the forest is virtually devoid of earthworms of any variety. It's one reason why maple roots are so shallow that they run along the open ground, in order to forage for decomposing humus on the forest floor, as opposed to deep underground, following the nutrition that comes from the earthworms burrowing just below the frost line for winter survival.
The Torreya taxifolia is similar in appearance to a distant cousin that I also grow, the Cephalotaxus fortunei, which grows broadly conical and 'bushy' to about 20 feet. But a key difference is that the latter will grow in most any type of soil conditions and light conditions in as cold as a USDA zone 5 climate. The outer limits of zone 5 winters will cause problems with some of the Cephalotaxus trees, but a friend on Dave's Garden seems to think that the reason the ones planted next to a pine stump seem to fare better is for the reasons I've listed above.
Visit Jeff's ongoing photo-illustrated webpage of his Torreya propagation work.
BEWARE OF RODENTS!
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. Below is a report by Les Eastman after finding that squirrels raided pots right next to his home.LES EASTMAN: "February in Florida was a cold month, colder than usual. Temperatures in central Florida were I live dropped to 20 degrees. The forecasters said it was going to be cold due to the Canadian freeze dropping temperatures south. I felt this would be a good time to stratify 10 Torreya seeds I had in pots next to my small greenhouse. One day I went into my yard and spotted a gray squirrel in my pots of planted seeds. The squirrel had gotten into all my pots; all seeds were gone. I had never figured that squirrels were able to smell buried seeds especially those that appeared to have no odor. Our neighborhood is loaded with scrawny gray squirrels. WARNING FOR OTHERS!If "free-planting" seeds directly into forest soil (not landscaping!), never plant anywhere near a bird feeder, as dropped seeds may have created a giant population of squirrels, chipmunks, and voles. Also, know that voles will probably be under logs, keep seed plantings away from logs.
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!
PHOTOS BELOW: In 2016 Connie Barlow video-recorded the sudden, over-winter deaths in this fashion of three previously lush-growth young Torreyas. You can watch the video segments at: 2 Torreyas killed at roots in Junaluska NC and 1 Torreya killed in Brevard NC. (The previous links will take you to the exact timecodes within the long videos where the dead trees are discovered.)
PHOTOS ABOVE: These are stills taken from the video 19a above. They show how a once-healthy planting can suddenly die owing to a rodent tunnel that is clearly chimpmunk-size. See how the roots and the living bark have been entirely gnawed away. Notice the light-colored pellets in the root photo; these are perlite. See the editor's note directly below about the importance of shaking out the perlite to deter rodent burrows! Also, in the video itself you will hear Connie remarking on the unusually compact soils and impoverished forest understory (probably owing to excessive cattle pasturing in the past). Perlite + surrounding packed soils we now know will vastly increase the rodent herbivory prospects of even carefully tended outplantings.
Photo left was taken in Spring 2016 by Connie Barlow at the Corneille Bryan Native Garden (Junaluska) site near Waynesville NC. That was where Torreya Guardians planted 10 potted seedlings in July 2008.
The photo left shows a rodent tunnel and rodent-gnawed roots of what, until Winter 2015, had been a vibrant little Torreya (Wangari Mathai). A second such planting (Lucy Braun) was discovered likewise killed the same day.
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.
These 2016 rodent-kill observations now confirm that perlite and soft soils must be shaken from the roots when out-planting potted seedlings!
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).
ABILITY TO RECOVER FROM HERBIVORY
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!
Photo above left by Connie Barlow of 2 seedlings donated by Jim Thomson (Cullowhee, NC) to Bob Miller of Loveland, OH (who took the photo above right).
Photos below by Nelson Stover in sequence Nov 2016, May 2017, and Nov 2017 shows herbivore devastation followed by recovery (both budding from stem and emergence of basal sprout).
BEWARE OF SNAILS during germination
Torreya Guardian Lamar Marshall told Connie 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.
ORCHARD STYLE (full sun)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.
Planting 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 some conifers may epigenetically acclimate to different climates during the within-seed embryo maturation phase. A 2008 paper reports that White Spruce seems to modify its "genetic" capacity to grow and the timing of bud set in accordance with the warmer or cooler conditions in which the embryo of a seed matures: "Timing of bud set in Picea abies is regulated by a memory of temperature during zygotic and somatic embryogenesis". IF TORREYA acclimates to the conditions of seed embryo maturation, then there would be considerable thrival/survival value to planting the seed directly into the target range soil (or at least putting seeds immediately post-harvest into rodent-proof beds near where the out-planting is to occur).
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 at least 3 inches deep (4 to 6 inches may be best). 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 are not given any wire protection upon germination:2A. PLANT SEEDS WHERE DEER ARE LEAST LIKELY TO VENTURE: Possibilities include a deep densely vegetated ravine and the steepest slope you can find. Possibly within the thicket of branches of a recent treefall.
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.
• 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 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:
I 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.
♦ 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: In the photos below of 5 emergent seedlings, you will see that the seedling always emerges from the upslope edge of the rock.
RECOMMENDATIONS FOR ADDITIONAL EXPERIMENTS:2018 UPDATE: 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.
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.
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.
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.
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.
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%.
Whether the remaining 80% of the seeds failed to germinate, were dug up and eaten by squirrels, or may germinate in future years is unknown. But the Stover experiment sets (thus far) a superb "free-planting" success rate of 1 in 5.
Note: See the kink in the lower stem. Nelson reports that a branch probably fell on it, as the setting is wild. "I found it while clearing off the leaves."
FRED BESS (Cleveland OH planter, MAY 2014) stratified 150 seeds this winter in damp peatmoss, and discovered that 27 of them had already germinated and begun to grow. 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.
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.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. 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.
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.
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:
Learning from California Torreya Habitats
Click for Site Visit by Connie Barlow in 2005
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.
JEFF MORRIS surmises: "As long as human intervention is available, a sunny spot along the outer edge of the forest, or a nice clearing, or even a clear-cut forest with leftover pine stumps, may provide ideal locations for the seedlings [of the eastern USA]. In the effort to help the 'struggling saplings' that must endure intense shade, it is my belief that planting these seedlings alongside rotting pine stumps will provide greater nitrogen-fixer assistance through chemical reactions and slight heat of the decaying stump. As Connie wrote, perhaps the natural lifecycle of the T. taxifolia indeed does include a dormant, 'struggling' phase over a substantial period of time.
"Also, perhaps seeds planted by squirrels in intense shade have less of a chance at survival, and the happenstance of an occasional nearby felled tree is what is necessary to permit the tree to grow to reproductive maturity. That's acceptable for squirrel naturalizing. But human assisted migration must be more judicious in selecting the micro-habitat 'niche' for now. Of the thousands of acorns my oak tree produces each year, I doubt three or four will make it to maturity, if that. It's just the process of uninterrupted natural selection. But with the Torreya taxifolia, at this stage of the assisted migration challenge, I feel an obligation to try to make every planting as successful as possible."
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.
PHOTO 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.
PHOTO 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.
PHOTO 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 2013, it is still doing well, though it is slow-growing).
PHOTO 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.
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.
PHOTO 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.
PHOTO 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. The same growth pattern can be seen in the PHOTO ABOVE RIGHT, where the logging of a single-stemmed Coast Redwood in California resulted in a massive set of resprouting basals. (Photo Connie Barlow, Humbolt County, 2017)
Assessing the Danger of Deer
ADVICE BY CONNIE BARLOW: 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.
PHOTO ABOVE LEFT: A young Douglas Fir (in Colorado) scraped by a deer.
PHOTO 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 that no deer would come near them.
PHOTO 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.
How Far North Will "Florida" Torreya Grow?
Because Torreya taxifolia has been "left behind" in its peak glacial refuge in northern Florida for more than 10,000 years, an important question is to experimentally discover just how far north its current habitable range actually is.
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?
FIELD EXPERIMENTS IN NORTHERN STATES ARE NEEDED to test leaf and bud survival in northern states, and ultimately 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. Fred shows how healthy the tree looks despite -17F degree winter temperatures in 2014. Visit Fred's Torreya Ohio page to watch a VIDEO of him showing us his trees.
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.
OCTOBER 2018 UPDATE: Cleveland OHIO Torreyas produce 23 seeds
• VIDEO: "Seeds of Florida Torreya Produced in Ohio".A crucial threshold was reached in 2017 and 2018 (by Fred Bess) when this set of 2 male and 2 female torreyas in Cleveland produced seeds. The tall female produced 5 seeds in 2017 and 18 or 19 in 2018. The shrubby female began producing seeds in 2018 just 4 this first year.
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.)
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
Part 1: MUST CUT TOPS OFF 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.
Part 2: 2017 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).
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.
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Part 3: 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."
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 (May 2017): "Cuttings taken in mid November are reluctantly rooting, so I want to date how many of those actually root. It would be good to have more information before I commit to saying what works or how well cuttings work. Thus far, August cuttings are the winners, mid September seems fine, and November seems slow. More time is needed to see."
EDITOR'S NOTE ON CUTTINGS: As of September 2017 we have no clear observations (and varying predictions) on whether Torreya cuttings clipped from lateral branches and then rooted can ever be nurtured into producing vertical trees v. the usual shrub-like growth form. And no one has yet confirmed whether clipping and rooting the vertical leaders of basal sprouts produces better tree-form results. However, I have just video-documented a redwood grower (Denise Rushing) in California who confirms that rooted lateral branchlets produce squirrely branches in their early years and continue to do so at their lower lateral levels even after staking them finally yields a singular and strong vertical leader that begins producing the tree form. Go to timecode 28:06 of the video by Connie Barlow, CTL 9E - California Sequoias to Inland Pacific NW: Is it too dry?, and there you will see images of the strange lower branches but strong top leader, while Denise talks about her nurturing of this redwood sapling. font face="Verdana">
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Part 3: 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. * * * * *
Part 4: 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.
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:
Part 4: ACHIEVING VERTICAL GROWTH FROM ROOTED BRANCHLETS
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.
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."
Photographs of Torreya taxifolia Conservation Program
at Atlanta Botanical Garden
(Photos taken by Connie Barlow in December 2007)
Seeds (5 or 6 to a pot, coded by mother tree) are planted immediately after harvest in autumn and after the sarcotesta (fleshy skin) has been removed. Here, the inch of soil covering the seeds has been scraped away for viewing.
Pots, like that in Photo A, have been set on the outdoor ground and covered with more potting soil. Here they will spend the winter, expected to germinate in April or May of the first spring. This location is in full shade beneath an evergreen canopy, and the pots are watered about every 5 days.
The wire mesh hinged lid that protects the potted seeds has been shut, to protect the seedlings from being dug up by squirrels, who highly favor them.
Ron Determann, director of plant conservation at Atlanta Botanical Garden, looks at Torreya taxifolia seedlings that sprouted from seed from the original genotypes in the garden's "potted orchard" that were produced in a series of different years. ABG is looking to distribute these and other seedlings (for free) to botanical and garden institutions who are interested in participating in the project to safeguard this highly endangered conifer native to northern Florida and southern Georgia.
An outdoor holding area for various-age seedlings, awaiting replanting in native FL and GA habitat or shipment to participating institutions. Notice the black net canopy to protect the seedlings from too much sunlight and heat.
Seedlings of Torreya taxifolia are sprinkled with lime (visible as white powder on soil surface) every 5 months or so, in order to guard against overly acidic soil conditions in which pathogens can get a hold. Notice that the pots are resting on outdoor soil, to encourage micorrhizal fungus associations.
Misting room in which Atlanta Botanical Garden roots branch cuttings from imperiled gymnosperms and other plants, including Torreya taxifolia and Florida yew (Taxus floridana).
In the misting room, a wide variety of gymnosperms and other plants are rooted from branch cuttings, such as those shown here. The "soil" matrix is white because it is made entirely of pumice, perlite, and ground-up sphagnum moss.
The outdoor "potted orchard" of pollen and seed producing specimens of Torreya taxifolia, which were rooted in 1991 from branch cuttings taken from individuals still growing in native, wild habitat of northern Florida and southern Georgia. Notice that the potted plants are kept outdoors, underneath the shade of mostly deciduous oaks. Orientation means that these trees are subject to direct sunlight during summer afternoons. ABG staff speculate that ideal aspect for Atlanta habitat for this species would provide morning sunlight and afternoon shade, to protect the trees from the worst summer heat. They also speculate that placement on a slope of well-drained soil would be ideal.
Even though this photo was taken in early December, male cones have already begun to form on branches of male T. taxifolia trees. Notice that the cones extend a ways down the branch stem.
Even though this photo was taken in early December, female cones have already begun to form on branches of female T. taxifolia trees. Notice that the cones form very close to the tip of the branchlet.
Photo L: Atlanta Botanical Garden uses mesh "cages" to surround and thus protect the growing seeds on female T. taxifolia trees from plundering squirrels. These hang on one of the specimens in the "potted orchard" depicted in Photo I.
Note: Atlanta Botanical Garden has to protect its ripening seeds from being harvested by squirrels because the seed-bearing plants are not "trees"; instead, they are sprawling shrubs, affording easy access to squirrels. The shrubby character of these seed-bearing Torreya specimens owe to the fact that they began as "rooted cuttings" of branchlets not seeds. And the "branch" that was rooted into a new main stem still "thinks" it is a branch on a mature tree, which induces it to begin producing seeds in perhaps a half dozen years of growth, rather than the normal several decades. The experience of Torreya Guardians harvesting seeds from mature trees in North Carolina is that squirrels cannot steal unripe seeds; the branches are too long, the leaves too prickly, and the seeds borne too far out on slim branches for any squirrel to be able to steal. Rather, the squirrels have to wait for the seeds to fall to the ground as ripe.
After the seed harvest, wire cages that protected the ripening seeds from squirrels are stored for next year's use.
One that got away: This seedling is growing right next to the fence in the "potted orchard" habitat. Because it is a volunteer, a squirrel must have gotten hold of a ripe seed, buried it, and failed to dig it up before germination the following spring.
This is one of the 1991 "mother plants" (rooted branch cuttings from wild stock) that was planted outdoors in the soil, rather than kept in pots. ABG would prefer to plant all such original genotype specimens in the soil, but space limitations means that most are consigned to spending their entire lives in large pots. For this reason, the 1991 "potted orchard" specimens that are still in pots (a) had their branches cut back in the summer of 2007, and (b) were "backed up" by cloning the harvested branches, thus to ensure that even if the original stems die, the exact genotypes are still available in a new generation of potted plants.
This is a close-up of the stems of the plant in Photo O above. Notice that no single vertical trunk is growing. This haphazard growth form is typical of specimens that began life as rooted branch cuttings. Only specimens that are grown from seed have the capability to develop trunks and grow into tall trees. The advantage of using rooted branch cuttings rather than seeds, however, is that rooted branch cuttings will themselves begin producing male or female cones much earlier than will specimens grown from seed.
Fabulous photos of a germinating Torreya seed at Arboretum de Villardbelle website.
Click left for a lengthy document of "best practices" for plant reintroduction practices in general
Click below for the 2012 "IUCN Guidelines for Reintroductions and Other Conservation Translocations". Note: This update of the guidelines makes a distinction between two forms of "translocations" that would be characterize conservation actions responsive to the ecological upsets of climate change:
ASSISTED COLONIZATION is the intentional movement and release of an organism outside its indigenous range to avoid extinction of populations of the focal species.
ECOLOGICAL REPLACEMENT is the intentional movement and release of an organism outside its indigenous range to perform a specific ecological function.