Common Name: Castor-Oil Plant

General Information

Ricinus communis is a much-branched, short-lived perennial plant with stout, hollow stems that become more or less woody and persist. A fast-growing plant in the wild, where it can grow up to 12 metres tall, in cultivation it is usually smaller, rarely exceeding 4 metresd[, , ].
The plant has a long history of cultivation as an oil-bearing and medicinal plant, having been grown in ancient Egypt[]. It is still widely cultivated for its seed in tropical and sub-tropical zones[, ]. There are many named varieties, some developed for ornamental use and others for oil production[, ].
The plant is often cultivated as an oil crop and also as an ornamental. Its seeds, which are spread by birds and mammals, an lie dormant in the soil for several years until disturbed. The plant often escapes from cultivation and establishes itself as a weed - fast-growing from seed, it forms thickets that shade out native flora. It has been declared a weed in many countries[].

Known Hazards

The whole plant is very poisonous[, , ], even one seed has been known to be lethal to children[, , ]. There is no specific antidote[].
The seedcoat contains an extremely lethal poison, called 'ricin', that was once used by the KGB to dispose of their enemies[, ].
The leaves are only mildly poisonous[].
The toxic principle is water-soluble so is not found in the oil[].

Botanical References

Range

The original habitat is obscure, but probably northwest Africa. The plant is widely naturalized from the tropics to warm temperate regions.

Habitat

Not known in a truly wild situation.

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	1.50 m
Growth Rate	Fast
Pollinators	Wind
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

A plant of the tropics and subtropics, it can also be grown as a summer annual in temperate zones. It can be found at elevations up to 2,000 metres in the tropics. It grows best in areas where annual daytime temperatures are within the range 20 - 30°c, but can tolerate 15 - 39°c[]. The seed may fail to set if temperatures rise above 38°c for an extended period[]. When dormant, the plant can survive temperatures down to about -2°c, but young growth can be severely damaged at 0°c[]. It prefers a mean annual rainfall in the range 600 - 1,000mm, but tolerates 400 - 2,000mm[].
Prefers a well-drained moisture retentive clay or sandy loam in full sun[, ]. Requires a rich soil[]. Prefers a pH in the range 5 - 6.5, tolerating 4.5 - 8[].
The plant requires 140 - 180 days of warm temperatures in the growing season in order to produce good crops of seed[].
Providing the plants water needs are met, yields of around 1 tonne per hectare have been achieved, with exceptional cases of up to 5 tonnes per hectare[].
Plants can continue yielding for 8 - 12 years[].
Plants may need support in exposed areas[].

Edible Uses

The seed contains 35 - 55% of an edible oil, used in cooking[, ]. It is used by the food industry to add butter and nut flavours to various foods[].The seed is a rich source of phosphorus, 90% of which is in the phytic form[]. Some caution should be observed, see the notes above on toxicity.

Medicinal

The oil from the seed is a very well-known laxative that has been widely used for over 2,000 years[]. It is considered to be fast, safe and gentle, prompting a bowel movement in 3 - 5 hours, and is recommended for both the very young and the aged[, ]. It is so effective that it is regularly used to clear the digestive tract in cases of poisoning[]. It should not be used in cases of chronic constipation, where it might deal with the symptoms but does not treat the cause[]. The flavour is somewhat unpleasant, however, and it can cause nausea in some people[]. The oil has a remarkable antidandruff effect[]. The oil is well-tolerated by the skin and so is sometimes used as a vehicle for medicinal and cosmetic preparations[].
Castor oil congeals to a gel-mass when the alcoholic solution is distilled in the presence of sodium salts of higher fatty acids[]. This gel is useful in the treatment of non-inflammatory skin diseases and is a good protective in cases of occupational eczema and dermatitis[].

The seed is anthelmintic, cathartic, emollient, laxative, purgative[, , ]. It is rubbed on the temple to treat headache[] and is also powdered and applied to abscesses and various skin infections[]. The seed is used in Tibetan medicine, where it is considered to have an acrid, bitter and sweet taste with a heating potency[]. It is used in the treatment of indigestion and as a purgative[].

A decoction of the leaves and roots is antitussive, discutient and expectorant[]. The leaves are used as a poultice to relieve headaches and treat boils[].

Agroforestry Uses:

The growing plant is said to repel flies and mosquitoes[, , , , , ]. When grown in the garden it is said to rid it of moles and nibbling insects[, , ].
The plant is traditionally grown in living fences in the northwestern Himalayas, where it helps to exclude livestock and other animals; mark out land boundaries; whilst also providing a range of medicinal and other uses[].

Other Uses

The seed contains 35 - 55% of a drying oil. As well as being used in cooking, it is an ingredient in a wide range of commodities including imitation leather, soaps, polishes, flypapers, paints and varnishes[, , , , , ]. It is also used as a lubricant and for lighting and as an ingredient in fuels for precision engines[, , ]. The oil is used in coating fabrics and other protective coverings, in the manufacture of high-grade lubricants, transparent typewriter and printing inks, in textile dyeing (when converted into sulphonated Castor Oil or Turkey-Red Oil, for dyeing cotton fabrics with alizarine) and in the production of 'Rilson', a polyamide nylon-type fibre[]. The dehydrated oil is an excellent drying agent which compares favourably with tung oil and is used in paints and varnishes[]. The hydrogenated oil is utilized in the manufacture of waxes, polishes, carbon paper, candles and crayons[].

A fibre for making ropes is obtained from the stems[].

The leaves have insecticidal properties[].

Cellulose from the stems is used for making cardboard, paper etc[, ].

Propagation

Seed - sow early spring in a warm greenhouse in individual pots. When they are large enough to handle, prick the seedlings out into individual pots and plant them out after the last expected frosts[]. The seeds retain their viability for 2 - 3 years[].