Styrax: Japan’s Lovely Snowbell Trees
The graceful Styrax, Japanese Snowbell, is a deciduous tree native to Japan that bears bell-like white flowers in late spring.
The Seattle Japanese Garden is graced with two species of Snowbell Tree, native to Japan, China and Korea. Both are excellent, pest and disease-resistant small trees.
There are two Styrax japonicus, Japanese snowbell tree (ego-no-ki), in the garden, both near the pond. The plant in Area Q, on the pond’s west side, has been pruned into a very low, espaliered form. The plant in Area F has achieved its natural form and height, and is more prominent after the removal of a large conifer that was shading this area.
Japanese snowbell is a graceful deciduous tree, about 30 feet tall and wide at maturity. It tends to be multi-stemmed, but is often pruned to a “tree form,” with a central trunk/leader. It has delicate branching and dainty bell-shaped flowers in May to June. The small, long-stalked flowers are usually white (sometimes pink) and lightly fragrant, massed on the undersides of the small branches (the current season’s growth). Each “bell” is formed of five petals, with prominent yellow stamens inside.
The small, oblong leaves are dark glossy green, and are held alternately on the branches. Fall color is yellow.
The fruits are attractive, greenish-white, egg-shaped capsules, appearing in September and persisting for many months. With their long stalks, and calyxes that seem to form a “hat” on top, they resemble holiday tree ornaments. Inside are hard seeds, which germinate readily. It’s common to find seedlings nearby and underneath older trees.
Full sun or open woodland conditions, with moist, well-drained, humus-rich soil, are ideal.
The Japanese snowbell is planted in gardens and parks in Japan, and also used as a street tree.
Historically, the very hard wood was used to make toys and the ribbing of umbrellas. Shapely trunks and branches were used for walking sticks, and as rustic supports in teahouses. The seeds were used to make an insecticide. The dried seed skins, which contain a soaplike substance (saponin), were used to wash clothes. In addition, fishermen made the skins into a powder, mixed it with ash, and threw the mixture into the water. This stunned the fish, which floated to the water’s surface and were caught very easily.
The garden has only one specimen of the other snowbell species, Styrax obassia, known as fragrant snowbell tree (hakuun boku, or oba jisha). It’s coarser in texture and narrower in habit than S. japonicus. According to Dan Hinkley, a local plantsman famous for his encyclopedic plant knowledge and plant hunting expeditions, this species is:
“one of the best of the hardy species…[and] forms a distinctive tree with bold textured foliage along a stout-lined framework to 30 feet by 20 feet. In late spring, splendid terminal racemes, slightly pendulous, carry large drooping bell-shaped flowers of white with a heady perfume. Hardy to Zone 5, it is not encountered in gardens of North America nearly to the degree that it could be.”
Located just south of the teahouse garden (roji), it’s shaded by other trees and so is prominent only when viewed from the west. In addition, its beautiful flowers are partially hidden by the 3 to 6-inch leaves, larger and more rounded than those of S. japonicus, and downy on the undersides. Thus, the flowers tend to be appreciated primarily for their fragrance. Fruits are similar to those the Japanese snowbell, but are covered in a velvety down.
Preferred growing conditions, are similar to those of its daintier relative. Fall color is a paler yellow.
In Japan, fragrant snowbell is frequently used as a street tree. Because of its upward-spreading branches, and taller-than-wide habit, this is an excellent use.
Historically, its wood was used to make implements and the pieces for Japanese chess.
Both species are wonderful small trees that should be planted more widely in the U.S. -- in residential gardens as well as parks. Although they lack the wonderful foliage shapes and colors of Japanese maples, they play a similar role in the garden – as graceful “understory” trees with 4-season presence. This includes their fleeting mid to late-spring flowers, dainty fruits, and the living architecture of their elegant winter branching.
Corinne Kennedy is a trained guide for Seattle Japanese Garden and a contributor to the garden's blog.