This beautiful herbaceous plant can reach 3 metres in height. In addition to its resemblance to the maple (thanks to its palmate leaf), the castor oil plant, Ricinus communis, is useful in particular thanks to its seeds, from which the oil is extracted. However, we must remember that, despite its beauty in flowerbeds and parks, it is dangerous. The ricin contained in a large part of the plant is extremely toxic.
Ricinus is the Latin word for ticks, due to the resemblance between the seeds and those parasites once they have gorged themselves on blood. Communis means “common”, in Latin.
Description and flowering period
Ricinus communis is an herbaceous perennial commonly reaching up to 3 meters in height and as much as 10 meters in some parts of its natural range. The leaves are palmate (with 5 to 7 pointed lobes), have toothed margins, are green in colour with more or less marked reddish veins. They are joined to the plant’s stalk by 30cm long petioles (leafstalks). The flowers develop in clusters in which the female flowers are on top (green with red stigmata) and the male flowers are at the base (grouped yellow stamens). The fruits are red round capsules covered in spines. They split in 3 parts upon opening. The seeds are beige marbled with red or brown and have a line on their ventral part. They contain between 40 to 60% of castor oil.
It prefers a rich and well-drained soil in a full sun location sheltered from strong winds. It is suitable for subtropical or warm temperate climates.
- Medicinal: It is a very strong purgative; the oil is also recommended as a treatment to stimulate lactation after childbirth.
- Cosmetics: The oil is used to encourage hair and lashes growth. Agriculture: It is planted between rows of potato plants to fend off potato beetles. Seed residue (after oil extraction) is also used as an organic fertilizer which also acts as a rodent repulsive.
- Miscellaneous: The oil is used for lighting, as a biofuel and as a lubricating agent for engines as well as bronze mechanical pieces.
The seeds are highly toxic (due to their ricin content) and must not be eaten. They can be deadly, especially if ingested by children or pets. The plant’s white latex can cause skin irritations and allergies. Ricinus communis is the only species within its genus.
Translated by: François Saint-Hillier – MNHN