Family: Euphorbiaceae

Status:

Description:
An open branching evergreen shrub 2 to 3m high with pithy stems. Leaves are very large (20-60cm in diameter), round in outline, but deeply lobed in a hand-like shape with up to 10 lobes. Crushed leaves have an unpleasant smell. Flowers are in terminal clusters with the red female flowers above yellow male flowers. The fruit is a large (to 3 cm diameter) spiny capsule containing three large seeds.

Preferred habitat and impacts:
Not widely naturalised on the south coast, but occasionally seen around towns in the northern part of the area. Generally only invades already disturbed sites such as forest edges, where it can prevent regeneration by native plants. Frost tender, it behaves as an annual in cooler climates.
The leaves are poisonous, and the seeds are very poisonous if swallowed (two seeds can kill a person). They are prettily marked in silver and brown, making them attractive to children. Despite their toxicity, they are the source of castor oil ,with which unfortunate children were dosed in earlier times to keep them "regular".

Dispersal:
Seed is ejected explosively for several metres, and can be spread in water, and in contaminated soil, or by slashing.

Look-alikes:
The white waxy bloom on the young stems and very large lobed leaves are quite distinctive, but one native plant, bitter bush (Adriana tomentosa, formerly Adriana glabrata) could possibly be mistaken for castor oil plant. Its leaves are smaller, but may be deeply lobed. It also has the pithy stems, and often grows close to water in disturbed situations. It is uncommon on the south coast.

Control:
Cut and paint mature plants, preferably before they begin to develop seed. Spray any regrowth. Seedlings may be hand-pulled or dug. Spraying should also be done prior to seeding, in spring or early summer. Follow-up control of seedlings will be needed for several years. Handle this plant carefully because of the seed toxicity.