Ricinis communis (EUPHORBIACEAE) Castor Oil Plant

Weeds to Whack

A perennial shrub with large leaves growing up to 4 m tall, a common weed of creek banks, neglected suburban blocks and other waste places. Not noxious in Queensland. It has been declared as a noxious species in New South Wales and the Northern Territory. Stems are hollow and hairless growing up to 2 m long, pale, dull green with a reddish tinge. Leaves arranged alternately on the stem with leaf stalks (petioles) 10-30 cm long, large (10-70 cm across) with seven to ten triangular lobes. Young leaves are often reddish-brown in colour.

Photo: Robert Whyte

Inflorescence with Red Stigmas – Female Flowers

Large inflorescences (flowering parts) form mainly during summer at the branch tips. The flowers are of separate sexes — fluffy cream or yellow coloured male flowers at the base of the inflorescence and female flowers with conspicuous red stigmas at the top. Fruit are greenish-red spiny capsules (15-25 mm across) which divide into three segments, each containing a single seed. Seeds are mottled and up to 1 cm long. They spread by seed which come up in their thousands on disturbed ground. Mulch will suppress them and also make it easier to pull them out if they appear.

Photo: Robert Whyte

Young Leaf, Poison Notes

Ricin is contained in the seeds. Ingestion of 2 to 8 seeds has resulted in death in adults. Ricin causes severe irritation of the throat, gullet and stomach when ingested. Gastrointestinal effects usually occur in under 6 hours. Late complications occur in the liver, brain, kidney, and adrenal glands, typically 2 to 5 days after ingestion. The individual may have a symptom free period between the gut symptoms and the multiple organ failures.
Photo: Robert Whyte