Castor aralia is found in Asia, including China, Korea, all main Japanese islands, Sakhalin, southern Kuriles and Ryukyu Islands. The plant is part of the humid temperate deciduous forests. It is found in a wide range of altitudes, from near sea level to areas with elevations higher than 8,000 feet. Castor aralia is the only species of the genus Kalopanax.
Castor aralia is a medium to large deciduous tree, which can grow 60 feet tall when cultivated or up to 100 feet in its native habitat. Leaves are glossy and dark green, featuring five to seven lobes each. Leaf margins have small teeth. Young trees have have on their trunks and branches that gradually disappear as the trees grow and mature. Castor aralia produces small white flowers in late summer, which become ripe black fruits in fall. The bark is dark gray, furrowed and ridged.
Castor aralia is a low-maintenance plant, easily grown in moist, deep soils. It tolerates light shade, but prefers full sun. The plant does not tolerate hot and humid temperatures, or dry soils. It is a hardy long-lived deciduous, highly adaptable to different levels of soil acidity or pH. It rarely shows serious disease or insect problems.
In Asia, the bark, roots and leaves of castor aralia are traditionally used as an anti-fungal and expectorant. In Korea, it has been traditionally used in the treatment of neuralgia, contusions, a disease of the nervous system called beri-beri, lumbago or low back pain and pleurisy, an inflammation in the lungs. Traditionally, the bark and leaves have also been used as an insecticide in Asia. The tree is also cultivated for timber in China.