Our only castor aralia came from the Arnold Arboretum at Harvard, which gave out trees to many schools around the country to celebrate its centennial in 1972. Biology professor Bert Brehm chose the tree and planted it in its present location.
The tree is native to China, eastern Russia, Japan, and Korea. It grows in moist places on the edges of forests, usually beside a river. The tree is in the same family as English ivy, and you can see a resemblance in the flowers.
Seeds of the castor aralia require a period of deep cold to germinate. The trees at Harvard produce hundreds of young seedlings, but the tree at Reed never produces any.