Culture
Best grown in rich, moist, fertile, well-drained sandy loams in full sun. Tolerates some light afternoon shade. Appreciates good air circulation. Water plants regularly and deeply in hot and dry summer periods. In St. Louis, site in locations sheltered from strong winds.
Noteworthy Characteristics
Platycarya strobilacea, commonly called platycarya, is a small deciduous tree that typically grows to 20-30’ tall (less frequently to 50’ tall) with a rounded crown. It will sometimes, particularly in less than ideal growing conditions, grow as a large shrub. It features compound pinnate leaves, separate male and female flowers in catkins that bloom in June-July, winged seeds in cone-like structures, and fissured rough gray bark. It is native to mixed forests on mountain slopes in China, Korea, Japan, Taiwan and Vietnam. Although it is a member of the walnut family, the fruits are inedible and resemble cones more than nuts.
Compound odd-pinnate leaves (to 12” long) have 7-15 sessile, toothed, ovate-lanceolate leaflets (each to 4” long). Cylindrical erect male catkins (to 3” tall) appear in clusters of 4-8 surrounding an erect female catkin which forms a cone-like structure to 1-2” long. Inconspicuous yellowish flowers on the green female cones bloom in late spring to early summer (June-July). Female cones mature to a showy chestnut brown as the fruits (winged nutlets to 1/8” across) form and ripen. Female cones remain on the tree throughout winter, providing excellent winter interest, before falling to the ground in spring.
Initially, Robert Fortune was credited with discovering this tree in China in May of 1844 at which time it was believed this was a new species, and it was accordingly named Fortunaea chinensis. Shortly thereafter, it was discovered that, unknown to Fortune, this tree had been described one year earlier (in 1843) in Japan by Philipp Franz von Siebold and Joseph Zuccarini and named Platycarya strobilacea. In matters of nomenclature, the earlier name has priority.
Genus name comes from the Greek words platys meaning broad and karya meaning nut in reference to the winged nutlets.
Specific epithet comes from the Greek word strobilos meaning rounded ball in reference to the rounded, cone-like, fruiting clusters.
Problems
Healthy, well-maintained plants usually have few major problems. Roots of this species produce chemicals (juglones) which are toxic to a variety of plants including azaleas, rhododendrons, blueberries, peonies, plus solanaceous crops such as tomatoes, peppers and potatoes. Adverse reaction to juglones should be considered whenever siting sensitive plants within the drip line of this tree (risks are much greater with walnut and butternut which release larger quantities of juglones into the soil than this species).
Uses
Tree is rare in cultivation. Interesting lawn specimen.