Castor Bean

Castor bean is usually direct-sown or transplanted as a tender warm-season annual, since it is killed outright by frost. It grows best in full sun in rich, moist soil, benefits from regular fertilizing, and has low drought tolerance until it becomes established. Because the stems are not wind-resistant, plants can be blown over and often need staking, and occasional pruning helps keep the shrub's shape; given a long enough season it grows quickly, becoming tree-like within three to four months, and reseeds itself readily.

Handling: Because every part of the plant is poisonous, growers are advised to wear gloves when working around it and to pinch off seed capsules while they are still small to remove the toxic seeds before they mature. It should not be planted where children or pets play.

Castor bean has no serious insect or disease problems; spider mites occasionally attack plants that have been stressed by drought.

Harvest: The spiny seed capsules change from green to pink or red before drying to brown, and each of the three sections splits open to eject its single seed with considerable force as it ripens. Storage: The seeds remain viable for two to three years after harvest.

Ornamental: Castor bean is grown for its oversized, star-shaped foliage and unusual spiny seed pods, used in the landscape as a specimen, container plant, or informal hedge.

Commercial: The oil pressed from its seeds, produced commercially in countries such as India and Brazil, is used in fabric coatings, paints and varnishes, inks, waxes, crayons, dyes, and ointments, while ricinoleic acid derived from it appears in spermicidal lubricants, cosmetics, and anti-fungal compounds; the leftover seed cake serves as a high-nitrogen fertilizer or, once detoxified, as livestock feed, and the stems have been used to make wallboard and paper products.

Medicinal: Castor bean has a long history in the traditional and folk medicine of Mediterranean and eastern cultures, recorded in ancient Egypt's Ebers Papyrus as a remedy for ailments including abscesses and baldness and used as an abortifacient and laxative; folk use elsewhere has included expelling intestinal parasites and treating wounds. In some traditions, the oil pressed from the seed, which does not retain the toxic ricin, has continued to be used as a laxative and as a topical application for skin complaints.

Castor bean is native to tropical East Africa, particularly the region around Ethiopia. Ancient Egyptian records, including the Ebers Papyrus compiled before 1500 BCE, show its seeds and oil already in practical and medicinal use, and from this early presence in northeastern Africa the plant spread through the Mediterranean world and beyond, eventually naturalizing across tropical and subtropical regions worldwide.