Ricinus communis L.
The castor-oil plant is not native to Istria and is rarely seen to be grown there. However, castor-oil's medicinal properties have been known and were used among the Istrian people. Gabriele D'Annunzio is credited for originating the practice of forcibly dosing opponents with large amounts of castor oil to humiliate, disable or kill them during the brief period when he occupied Fiume (now Rijeka, Croatia) and declared himself dictator. This practice became a common tool of Fascist dictator Benito Mussolini and was used in Istria during the period of Italian rule between the two World Wars.
Ricunus communis is a single gigantic herb (tree-like in the tropics), and the only species of the genus Ricinus (ris'i-nus) of the spurge family. The castor oil plant is cultivated widely in the tropics and subtropics and in temperate latitudes. It is grown for commercial and medicinal applications, as well as for ornamental use in gardens, sometimes as a houseplant, and it also grows as a weed. It is an annual in the south and a perennial in the tropics.
Family: Euphorbiaceae (spurge family)
Biological name: Ricinus communis [and also Ricinus dicoccus?]
Common names: Castor-oil plant, Castor, Castor bean, Castorseed (English), Eranda, Vatari, Rendi, Bofareira, castor-oil plant, Mexico seed, oil plant, Palma Christi, Cici/Kiki (by the ancient Egyptians, according to Pliny) Higuerilla (Spanish), Ricin (French), Ricino (Italian), Bherenda (Bengali), Rehri, Erand (Hindi), Amanakkum (Tamil), Gandharv Hasta (Sanskrit), Chittamanakku (Malyalam), It is also known as Amanakkam-chedi, Amanakku, Amidamu, Amudam, Arand, Aranda, Audla, Avanakku, Ayrunkukri, Bedanjir, Bherenda, Chittavanakku, Chittmani, Diveli, Endaru, Endi, Eramudapu, Erand, Erendi, Erandthailam, Eri, Gandharva Haralu, Hasthah, Gemeiner Wunderbaum, Heran, Kesusi, Khirva, Miniak-jarah, Panchangulam, Ricinus, Sadabherenda, Verenda, and probably by other names as well.
The scientific name for the castor plant, Ricinus communis, has a much more logical derivation. Communis means common in Latin, and castor plants were already commonly naturalized in many parts of the world when the eighteenth century Swedish naturalist Carolus Linnaeus (Karl von Linné) was giving scientific first and last names to plants and animals over 200 years ago. Ricinus is the Latin word for tick and is the specific epithet for the Mediterranean sheep tick (Ixodes ricinus). Apparently Linnaeus thought the seeds looked like ticks, particularly large ticks engorged with blood. [See Castor Seed below.]
In frost-free areas, castor bean is an evergreen herbaceous or semiwoody large shrub or small tree that gets up to 40 ft. (12 m) tall and 15 ft. (4.6 m) wide. In the tropics, it can have a trunk that is woody near the base and up to a foot in diameter. Elsewhere, castor bean plant grows as an annual that can get 8-15 ft. (2.4-4.6 m) tall in a single growing season. This is a fast growing, suckering, colony forming plant with decidedly tropical looking foliage. They tend to grow straight up at first, developing branches only later in the season (and in subsequent years for plants that live that long). The huge leaves are palmate, with 5-11 deeply incised lobes. They are glossy purplish or reddish-green and 12-30 in (30-76 cm) across, with long petioles (leaf stems). The stems are watery juicy and reddish or purplish too. The inflorescence is not particularly showy; small, 0.5 in (1 cm) wide greenish yellow flowers are borne in fat spikes 8-18" tall near the tops of the stems.
A terminal raceme of flowers appears in later summer. Female flowers are on the top half of the spike and have conspicuous fuzzy red stigmas (the parts that receive the pollen). The male flowers on the lower half of the spike have conspicuous yellow anthers (the parts that give off the pollen). The female flowers are followed by oblong or egg-shaped reddish-brown fruit is a soft and flexible spiny pod or capsule about an inch long. The pod turns brown when ripe and splits into three one-seeded parts. The seeds are smooth, glossy, black or mottled with gray or brown. The flat seeds explode out f the seed pod when ripen. They look like fat swollen dog ticks and are deadly poisonous.
There are several named cultivars, including some grown commercially for oil production, and this sampling of ornamentals: 'Carmencita' has bronzy red leaves and bright red female flowers. 'Impala' is small, 4-5 ft. (1.2-1.5 m) tall and has red leaves that age to reddish purple. 'Sanguineus' has blood-red stems and leaves. 'Gibsonii Mirabilis' is dwarf, only 4' tall, and has dark red leaves and stems. 'Zanzibarensis' is taller and has larger leaves that are green with white veins.
Location / Habitat
Castor bean was originally native to northeastern (tropical) Africa and the Middle East. It has escaped cultivation and become naturalized as a weed almost everywhere in the world that has a tropical or subtropical climate. Castor bean grows wild on rocky hillsides, and in waste places, fallow fields, along road shoulders and at the edges of cultivated lands.
In Suriname it grows as a common weed often in colonies, in the coastal region. Castor bean has escaped cultivation and established in waste areas, the edges of cultivated fields, canal banks, etc., in South Florida, but it has not become a serious pest weed. It is, however, listed as a Category II Species (has the potential to disrupt native plant communities) by the Florida Exotic Pest Plant Council. Castor bean is one of 34 species that the Florida Nursery Grower's Association's Board of Directors voted unanimously in March 2001 to no longer propagate, sell or use in Florida (click for press release). The California Exotic Pest Plant Council includes castor bean on their List B, defined as a wildland pest plant of lesser invasiveness than those on List A.
The tree is very variable in habit and appearance, the known varieties being very numerous, and having mostly been described as species. In the tropical latitudes which is most favorable to its growth, it becomes a tree some 30 to 40 feet in height; in the Azores and in the warmer Mediterranean countries - Algeria, Egypt, Greece and the Riviera - it is of more slender growth, attaining an average height of only 10 to 15 feet, and farther north in France, and in this country, where it is cultivated mostly as an ornamental plant, on account of its large and beautiful foliage, it is merely a shrubby branched annual herb, rarely more than 4 to 5 feet high.
As grown in the North, the castor-oil plant is a tender annual 48-150 in. high. The flowers are green and inconspicuous, but pink or red in the pigmented varieties. Many stamens are near the base and branching pistils are near the top of the flower. The soft-spined fruits containing attractively mottled seeds are distinctive features of the plant. Leaves alternate, often 3 ft. wide, 6 to 11 lobed, palmate and with uneven serrated edge, are red or colored and often have a blue-gray bloom, and there is also a green variety. The joints of the hollow stem, stalks and leaves are reddish to purple. The stalk is attached to the middle of the blade, which is divided nearly to the middle by several lobes. Flowers in a dense, terminal cluster often 1-2 ft. high, the individual flowers small, without petals, the sexes separate. Fruit a spiny pod (capsule) containing the beautifully marked, poisonous seeds. (Ricinus is the classical Latin name of this plant.)
The common castor-oil plant is usually grown in the form with green foliage, but there are several other varieties. One has much larger, green leaves. Another has red stems and bluish-gray leaves, and there are several with red and one with variegated leaves. One with white-veined leaves is offered as "mosquito-plant."
For further details on the plant's characteristics, see "Poisonous Plants Page, Ricinus Communis, http://res.agr.ca./
The castor bean seed coat contains ricin, one of the most poisonous naturally occurring chemicals known to Man; even very small doses can be fatal. Castor oil, derived from castor beans, is used extensively in medicine and in varnishes and paints, as a lubricant and lamp oil, and in many other industrial and manufacturing processes. The foul tasting laxative, castor oil, loathed by children everywhere, tastes poisonous but is, however, a valuable purgative still widely used in modern medicine. Castor oil also is used externally to treat some kinds of skin diseases including ringworms and warts. The genus name, Ricinus means "dog tick" in Latin, because that's what the seeds look like.
Parts used: oil, leaves, roots, seeds, fruit
Castor bean is very easy to grow; too easy, some might say. They like full sun and have a tendency to self sow and new seedlings can pop up all summer long. This is one of the fastest growing plants in the world and becomes almost tree-like in 3-4 months. It will need to be staked if grown where the wind can blow it over.
Hardiness: USDA Zones 8 - 11. Castor bean is a big evergreen shrub or small tree in zones 10-11, and is a tender perennial. It usually won't live through the winter, but can be expected to reseed itself in zones 8 and 9, and maybe in zone 7. Plants sometimes sprout back from the roots after freezing in zones 8B and 9. In zones with shorter growing seasons, - 7 (lower than seven) start sowing indoors at 8 (eight) weeks before last expected frost. Castor bean is widely grown as an annual in cooler climates and can tolerate a touch of frost.
Moisture: Castor bean grows fastest and largest with abundant water, but once it gets established, it can tolerate drought - it just won't grow as fast.
Propagation: seeds and cuttings. Castor bean seeds germinate quickly, and the plants grow very fast. They can be expected to self sow under favorable conditions. Germination can be hastened if the seeds are soaked in water for 24 hours or nicked with a file before planting. Sow in place in zones 8-11. In areas with shorter growing seasons, or to get a head start, sow seeds indoors in individual containers 6-8 weeks before the last expected frost.