Distylium racemosum, commonly known as the Isu tree, is an evergreen shrub or small tree native to forested areas, stream banks, and mountain slopes of subtropical eastern Asia, including central and southern Japan, the Ryukyu Islands, South Korea (Jeju Island), southeastern China, Taiwan, Hainan, and northern Vietnam. It typically grows to a height of 3-9 meters with a similar spread, and features a dense, rounded to spreading form. The Isu tree produces small, inconspicuous red flowers in late winter to early spring, followed by capsule-like fruits. Its leathery, glossy green leaves and the reddish-brown bark add year-round interest.

The Isu tree is valued for its low maintenance requirements, tolerance of a range of soil types, and resistance to drought and urban pollution, making it suitable for urban planting, hedges, and as a foundation plant in landscaping. It thrives in full sun to part shade and prefers well-drained soils. While generally pest and disease-free, it can occasionally suffer from leaf spot. Cultivars like ’Guppy’ with its compact growth habit and ’Akebono,’ known for its variegated foliage, offer additional ornamental appeal.CC BY-SA 4.0