Propagating Torreya Taxifolia?

Propagating Torreya taxifolia

Go directly to Propagating from SEEDS

Go directly to Propagating from BRANCH CUTTINGS

Click for the Importance of LIMING

Go directly to Propagation PHOTOGRAPHS

Fabulous photos of a germinating Torreya seed at Arboretum de Villardbelle website

Propagating Torreya taxifolia from SEED
(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.

WHEN TO PLANT SEEDS: A
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: Notes taken by Connie Barlow in December 2007, when 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.

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.

ADVICE FROM JACK JOHNSTON: A bit more about how Torreya can be rooted. The key is to keep the cuttings at 70 degrees, 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 is 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.
Part 2: Recommendations by Jack Johnston, based on his experience
propagating branchlets and seeds at his home in northern Georgia

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.

    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."

Photographs of Torreya taxifolia Conservation Program
at Atlanta Botanical Garden
(Photos taken by Connie Barlow in December 2007)

   Photo A
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.

   Photo B
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.

   Photo C
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.

   Photo D
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.

   Photo E
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.

   Photo F
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.

   Photo G
Misting room in which Atlanta Botanical Garden roots branch cuttings from imperiled gymnosperms and other plants, including Torreya taxifolia and Florida yew (Taxus floridana).

   Photo H
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.

   Photo I
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.

   Photo J
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.

   Photo K
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.

   Photo M
After the seed harvest, wire cages that protected the ripening seeds from squirrels are stored for next year's use.

   Photo N
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.

   Photo O
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.

   Photo P
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.



Smithgall Woods 2007 seed harvest sprouting
in northern Georgia (home of Jack Johnston).
Torreya sprouts. (Mesh deters squirrels from seeds.)

WWW www.TorreyaGuardians.org

		Photo A 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.
		Photo B 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.
		Photo C 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.
		Photo D 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.
		Photo E 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.
		Photo F 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.
		Photo G Misting room in which Atlanta Botanical Garden roots branch cuttings from imperiled gymnosperms and other plants, including Torreya taxifolia and Florida yew (Taxus floridana).
		Photo H 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.
		Photo I 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.
		Photo J 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.
		Photo K 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.
		Photo M After the seed harvest, wire cages that protected the ripening seeds from squirrels are stored for next year's use.
		Photo N 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.
		Photo O 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.
		Photo P 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.