Castor-oil Plant

Origin: 

Native to the southeastern Mediterranean Basin, Eastern Africa, and India.

Distinguishing features:

• Large, palmately lobed leaves: Leaves are typically 30-70 cm wide, deeply divided into 5-11 sharply toothed, pointed lobes, resembling an open hand. They can be green, bronze, or reddish-purple.

• Often reddish stems: Stems are stout, hollow, and often have a distinctive reddish, purplish, or glaucous (bluish-green) waxy coating, especially when young.

• Spiky, green to reddish seed capsules: Spherical, often three-lobed capsules, 1-3 cm in diameter, densely covered in soft, flexible, green to reddish-purple bristles. They split open when dry.

• Shiny, mottled seeds: Seeds are smooth, shiny, oval, and resemble ticks or beans, with variegated patterns of brown, grey, black, and white. They are highly toxic.

• Rapid growth: Grows very quickly, often appearing in disturbed areas or along roadsides.

Overall appearance: 

A robust, fast-growing, often ornamental-looking shrub or small tree. Its most striking features are its large, deeply lobed leaves and its distinctive, spiky seed capsules. The stems can range from green to vibrant reddish-purple.

Height: 

Typically grows 2 to 5 metres tall as a shrub in South Africa, but can sometimes reach up to 10 metres, especially in warmer, favourable conditions.

Width: 

Can spread 1 to 3 metres wide, forming a dense, bushy habit.

Leaves: 

Large (20-70 centimetres wide), alternate, simple, and palmately lobed, meaning they are deeply divided into 5 to 11 (or more) pointed, sharply toothed lobes, resembling a star or an open hand. The leaves are smooth, glossy, and can vary in colour from bright green to dark reddish-purple, especially on ornamental cultivars or in full sun. They have long leaf stalks (petioles) that attach to the centre of the leaf.

Flowers: 

Small, inconspicuous, and lack petals. They are borne in large, upright, greenish-yellow to reddish terminal clusters (panicles). Male flowers are at the bottom of the cluster with prominent stamens, and female flowers are at the top, characterised by reddish stigmas. The plant is monoecious (male and female flowers on the same plant).

Flowering season (South Africa): 

Flowers mostly from spring to autumn (around September to May), but can flower sporadically throughout the year in warm climates.

Fruits: 

Spherical, three-lobed capsules, 1.5 to 3 centimetres in diameter, covered with soft, flexible, green to reddish-purple bristles. As they mature, they turn brown and split open explosively, dispersing the seeds.

Seeds: 

Oval, smooth, shiny, and highly variable in colour, typically mottled with patterns of brown, grey, black, and white, resembling engorged ticks or patterned beans. Each capsule usually contains three seeds, about 1 to 2 centimetres long. The seeds are extremely poisonous.

Bark: 

On young stems, the bark is smooth, often waxy, and can be green, reddish, or purplish. On older, more woody stems, it becomes somewhat rougher, greyish-brown, and may be slightly ridged. The stems are typically hollow.

Thorns: 

This species does not have thorns on its stems, but its seed capsules are covered in soft, spiky bristles.

Wood: 

The stems are hollow and semi-woody, rather than forming dense timber. Not typically used for wood products.

Roots: 

Develops a strong, deep taproot system that allows it to access water in drier conditions, along with a fibrous lateral root system that aids in rapid establishment and absorption of surface moisture.

Soil type: 

Highly adaptable, thriving in a wide range of soil types, from sandy to clay, as long as they are well-drained. It tolerates poor or disturbed soils and is often found in nutrient-rich waste areas.

Aspect: 

Prefers full sun and warm conditions. It is tolerant of drought once established but sensitive to severe frost. It often establishes readily in disturbed open areas.