03. Prickly Castor Oil

Prickly Castor Oil Tree

Kalopanax septemlobus (Thunb.) Koidz.


Range: North-eastern Asia from Sakhalin and Japan, through to south-western China.

Introduced into horticulture by Carl Johann Maximovich in 1865.

  • A very hardy tree which copes with temperatures down to -40 degrees celsius.
  • The tree has rapid initial growth which will slow down after 40 years.
  • The name Kalopanax is derived from the Greek word Kalo meaning beautiful and Panax which refers to the Ginseng genus. The leaves have 5-7 lobes, usually 7, hence septemlobus.
  • The stems have large prickles and the flowers attract bees and other insects in late summer.

This plant is part of a monotypic genus, which means that there is only one species in the genus Kalopanax. The tree can tolerate temperatures down to -40c. As a member of the Ivy family (Araliaceae) the tree produces its flowers in late summer. The tree in front of you is thought to be one of the largest in the United Kingdom, known as a Champion Tree. You can find more information about champion trees of Britain and Ireland at www.treeregister.org/champion-trees.shtml

Missouri Botanical Garden website

Kelly, J. (1995) Hillier’s Gardeners Guide to trees and shrubs, David and Charles

Bean, W.J., (1989), Trees and Shrubs Hardy in the British Isles (8th edn) John Murray London