In our experience we found that cold stratification increases the germination rate. In soil, use the refrigerator or put them outside for a minimum of 2 weeks. If you chose a refrigerator make sure to put the seeds in moist soil in a zip lock bag. To protect our trees from wildlife, we've fenced our orchard.
While looking for more information on the Chinese Flowering Chestnut, we happened across a recently well written and informative article written by Mark Dwyer for the Nursery Management magazine. They have given us permission to use their wonderfully informative article on our website.
With its snowy and fragrant flowers, this striking shrub deserves broader availability in the trade.
The Yellow Horn (Xanthoceras Sorbifolium) is surprisingly underutilized in our North American landscapes although its availability is certainly associated with its obscurity (and vice versa). Also called Golden Horn, white raintree, and Chinese flowering chestnut, this small deciduous tree from northern China is hardy in Zone 4–7 and is surprisingly durable and long–lived once established. First collected and named in 1833, this member of the soapberry family (Sapindaceae) initially became cultivated in Europe (Paris) by 1868. Joseph Hooker, Director of the Royal Botanic Gardens — Kew (1865 – 1885), described this plant in 1887 as "one of the most attractive and interesting hardy garden shrubs that has been introduced in many years." Yellow Horn has also received the Royal Horticultural Society Award of Garden Merit which should hint at its potential value and impact in the landscape.
Yellow Horn features lustrous green, compound leaves that resemble the foliage of mountain ash (Sorbus), hence the specific epithet of sorbifolium. The pinnate foliage features of very narrow leaflets that are quite glossy. This plant certainly contributes a fine texture in the landscape and the fall color can range from a muted gold to a clear yellow. Yellow Horn will reach heights between 8–25 feet with a width of 10–15 feet in time and should be considered slow to moderate in terms of growth rate. This size fits right in between the loose definitions of a large shrub and small tree. With age, the form becomes more upright with stiff, coarse branching habit although the significant flowers (mentioned below) may bend the branches to a certain degree when at peak bloom.
Specimens are frequently multiple trunks although some are single trunks and branched fairly low to the ground. Yellow Horn may slowly colonize a space with some root suckering which is not a characteristic of every specimen. The fleshy, fibrous roots make this plant challenging to transplant which is noteworthy. The commonly observed high transplant mortality seems to be associated with sensitive root structure. Gentle handling is prudent during all phases of planting.
Blooming in May, the fragrant flowers, appearing on terminal racemes, are white with very light green streaks and a center that age from yellow on the newest flowers to a gorgeous red orange on older flowers. The proliferous flower clusters can be up to 10 inches long and individual flowers are roughly 1 inch in dimeter with five petals.
Another common name for this plant is "popcorn shrub" due to the appearance of the flowers upon opening. The duration of bloom is only about two weeks, but it is a gorgeous and memorable display. Plants as young as two to three years old will start to bloom readily. William (Ned) Friedman of the Arnold Arboretum (Harvard University) writes about the value of the yellow to red color shifts in the flowers of Yellow Horn and other woodies with similar flowering characteristic. Ecologists have shown that insects have an innate preference for yellow flowers over red and by targeting the younger with yellow accents; they are assured of more nectar and pollen. Those that have faded to red have likely been visited already. Friedman mentions that this yellow to red color shift has evolved to help steer insects to newly opened flowers.
The fruits, more common on older specimens, are 2 1/2–inch, pear–shaped, leathery capsules. The capsules are initially green and resemble a black walnut husk but later age to a brown and split open into three chambers that contain the glossy, pea–sized black seeds. The half–inch seeds are edible and when roasted, have the flavor of macadamia nuts. The seeds are also used to produce quality cooking oil and aside from being roasted, can be boiled or dried and ground into flour. Apparently, this plant also has edible flowers and foliage which are traditionally boiled in advance of consumption.
Yellow Horn can be found in Beijing, China as a small urban tree and is also commonly found throughout a wide range of other urban settings. There are actually large plantations of Yellow Horn in China as the seeds are showing great promise as a highly suitable biofuel.
Yellow Horn is commonly propagated from seed or cuttings (stem and root suckers). A higher germination rate for the seeds has been observed with three months of cold stratification. Soaking the seeds for 24 hours before sowing combined with scarification is also recommended by some sources.
The first challenge in growing Yellow Horn initially starts with sourcing it. Finding this plant will certainly be a quest but ultimately worth the time. This unique and beautiful woody plant has impressed those that have grown it over the many years since it was introduced into cultivation.
Yellow Horn doesn't mind slight dampness but is quite sensitive to excessive moisture or heavier soils that stay wet. In general, this plant isn't overly picky about soil although again, drainage is important. A loamy soil would be ideal but isn't essential for the success of this durable woody plant and slightly acidic to slightly alkaline soils are just fine. a pH range between 5.5 and 8.5 is recommended. Yellow Horn is very sensitive to too much shade where it will simply not thrive or flower well. A full sun location is ideal as is plenty of summer heat associated with that exposure. This plant has no significant insect or disease problems although coral spot fungus has been observed on occasion.
Keep in mind that Yellow Horn also flowers on old wood so any pruning should be accomplished immediately following the bloom cycle similar to the approach with lilacs (Syringa). An isolated Yellow Horn can still flower and fruit although multiple specimens will assure more significant fruiting.
There is a variety called Clear Creek ('Pagan') selected by Green Acres Nursery in Golden, Colorado, and promoted by Plant Select, which markets a brand of plants designed to thrive in high plains and intermountain regions. This selection has all the same features of the species but is thought to have increased cold tolerance and hardiness.
Whether Yellow Horn is used as a specimen plant, in a mixed border or as spring feature in a prominent location, it certainly deserves broader awareness, availability and enjoyment of its attributes.
Mark Dwyer was the Director of Horticulture as Royal Botanical Gardens in Janesville, Wisconsin, for 21 years. He has degrees in landscape architecture and urban forestry and now operates a private consulting practice, Landscape Prescriptions by MD. www.landscapeprescriptionsmd.com.
We have 1 year old potted trees for sale. They are about 6–8 inches tall in 4 inch tree pots. Once planted in the ground it will take them a couple years before you see any nuts grow on the trees. For pick up the trees are $11.95 and shipping is $14.95 with a minimum of 7 trees per order.
We are selling 50 seeds/nuts for $12.77 with free shipping so you can have this rare tree growing in your area. We have 300 seed/nut bags for $34.77 with free shipping. We also have 2lb bags, containing about 800 seeds, available for $79 with free shipping.
We ship the seeds/nuts in a clear/silver resealable bag.
Shiny Leaf Yellow Horn is a beautiful tree that has so much more potential than it is given.