After observing the Idesia polycarpa (wonder tree) for several years in our landscape at the nursery where I am employed, I am somewhat astonished that this tree is so obscure in the nursery trade. There is a great deal to love about this underutilized gem.
Idesia is a medium-sized deciduous tree with soft leathery leaves that have a slightly silvery underside, characteristic of many plants and trees in the Salicaceae (willow family), to which it belongs. Some elderly specimens have been reported at 60 feet tall, but a mature tree grows to about 35 feet in the few landscapes where they are found. Most references describe this tree to be fast-growing; however, our specimen in Oregon has grown from a sample in a #5 nursery container to a 15-foot tree in 15 years, so I would argue that it has a well-behaved, moderate growth habit, at least at this location.
While the willow family is a large one, Idesia polycarpa is a unique genus with only one species. There are isolated reports that at one time a curly leaved subspecies, ‘crispa’, existed, but evidence seems to be limited to a few botanical drawings from the 1800s. If there is a living sample, I have not been able to find any references to it. A variety found in some New Zealand nurseries, ‘Kentucky Fry’, is advertized as self-fertile. In the United States, it seems to only be found in the Norfolk Botanical Garden in Virginia.
COMMON NAME: Wonder Tree, Igiri, Shantongzi
HARDINESS: Zones 6 to 9
MATURE HEIGHT: 35 feet
MATURE SPREAD: 30 feet
CLASSIFICATION: Deciduous tree
LANDSCAPE USE: Specimen tree, shade tree
ORNAMENTAL CHARACTERISTICS: Small, fragrant flowers, large clusters of abundant red fruits
Native to Eastern Asia, it can be found in Taiwan, China, Japan and Korea. Like many plants native to this area, Idesia is hardy in USDA zones 6 to 9, making it a wonderful option for many U.S. gardeners. It prefers moist, well-drained soils that are neutral or slightly acid.
Idesia exhibits multiseasonal interest, something most landscapers and homeowners strive for. In winter its smooth, pale-gray bark matches the muted winter palette, and in spring, tiny fragrant yellow flowers emerge. While they are not showy, they are interesting and their fragrance travels well. During summer, its luxurious canopy makes it an excellent shade tree.
But its claim to fame is the big fall finale, where copious qualities of scarlet-red berries in large, dense panicles droop from every branch. It is easily the most prolific bearer of ornamental fruit that I have seen, rivaling other, more popular ornamental trees with showy fruits, such as Sorbus or Crataegus. While it does not sport impressive fall leaf color, the berries more than make up for it. The fruits are edible either raw or cooked, although having tasted one raw I would say I am reluctant to add it to my salad. The persistent fruits last well into winter, providing much welcomed fruit to birds and other wildlife.
Idesia is easy to propagate by seed; however, the resulting plants, like anything propagated by seed, can be variable. Although somewhat difficult, experiments at Longwood Gardens in 2009 to 2010 show that softwood cuttings dipped in a 10,000 mg·L−1
solution of K-IBA solution of K-IBA rooting hormones seemed to yield the best results.
If there’s a downfall to this tree, it’s that it is dioecious, requiring a male and female tree for heavy fruit set. In nurseries that grow other types of dioecious plants, such as Ilex or Skimmia, the male and female are often in the same pot. Some nurseries, mostly outside the U.S., have had success with grafting male scion to female trees. These options, or obtaining scion wood from the self-fertile variety, may make growing this beautiful tree a more viable option for commercial growers.