Alangium platanifolium is the first in a series featuring plants showcased in UBC Botanical Garden’s newly released book: The Jade Garden – New and Notable Plants from Asia.
This outstanding understory shrub can become a small, wide-spreading tree of considerable beauty at maturity. At UBCBG, we received this species from Hilliers Nursery, United Kingdom, under the variety macrophyllum (Sieb. & Zucc.) Wangerin. The plant is better placed into Alangium platanifolium as part of the natural variation within this species. The profile of this large shrub is initially vase-shaped in youth and gradually broadens with age to form a flat oval top up to 4 or 5m high by 5m across. It can have a short bole before dividing into several horizontal laterals that may display an undulating muscular appearance. The main branches then divide into dense clusters of twigs at the extremities. These characteristics contribute to a winter silhouette that is both distinctive and ornamental. The shrub adapts well to semishaded forest edges or as a shade-tolerant understory plant in the wild or in cultivation.
The large (16-21cm long by 13-15cm wide), broadly ovate yellowish green leaves resemble those of the London plane (Platanus × hispanica). They are variable in shape but are generally tri-lobed, forward pointing toward the apex, with cordate bases. Often the acuminate lobes are twisted, adding to the distinctive foliar texture of this plant. In the spring the leaves unfold in the manner of hands in prayer and then turn a glorious yellow in the autumn. The flowers are white and appear in late June along the undersides of main horizontal branches often hidden by the verdant foliage. They are borne in 1- to 4-flowered cymes from the leaf axils of the previous year’s growth. Each flower consists of 6 petals narrowly strap-shaped and slightly twisted, forming a corolla tube at the base. Each petal reflexes to the midpoint to expose the bright yellow stamens and style. The pendulous, fleshy, egg-shaped fruit, coloured porcelain blue to dark violet, provides a stunning contrast to the golden fall leaf display.
The larger leaf variants occur widely throughout the species’ native distribution, growing as an understory shrub in Japan with a host of ornamental forest dwellers such as Cornus kousa, Lindera obtusiloba and Helwingia japonica. The huge natural range of this plant could provide horticulture with a broad spectrum of ornamental variation and environmental tolerance.