Castor aralia (Kalopanax septemlobus)

Features and Characteristics

Kalopanax septemlobus, commonly called castor aralia or tree aralia, is the only large tree found in the aralia family. Its large leaves are reminiscent of castor bean. This deciduous tree typically grows to 40-60’ tall with an upright oval habit. In its native habitat, it occurs in cool, moist forest areas and may reach 90-100’ tall. Palmate, toothed, glossy, dark green leaves (7-14” wide) have 5-7 lobes (septemlobus meaning 7 lobes). Leaves turn dull yellow to red in fall, but are not particularly showy. Trunk, branches and particularly the younger stems are armed with spines. Spines tend to disappear from the trunk and larger branches as the tree matures. Tiny white flowers appear profusely in large, terminal, umbel-like panicles (12-24” wide) in late summer. Tiny black fruits in compound clusters ripen in fall. Fruits are attractive to birds. Dark gray bark is ridged and furrowed. Synonymous with Kalopanax pictus.

Genus name comes from the Greek word kalos meaning beautiful and Panax the name of a related genus.

Specific epithet means have 7 lobes.