Euphorbia stellispina is a stunning architectural plant that is a true survivor in the harsh landscape of the central Karoo and parts of Namaqualand.
Euphorbia stellispina is a tall, unisexual, multi-branched, spiny succulent. Plants under ideal conditions can attain a height of 0.6-0.75 m. The plant can produce up to twenty branches. The overall shape of the plant is clump forming. The branches of the stem are 40 to 750 mm thick and have ten to sixteen angles on them. Branches are upright and are heavily armed with spines. Flowers which are light yellow are borne on or near the terminal apex (top part of the plant). Seed is produced in copious amounts. The seed capsules are trilocular (they have three compartments each with one seed in it). As the seed capsule dries they burst and its contents are catapulted out and so these seeds start the next generation.
Euphorbia stellispina has a very wide distribution, stretching from Gordonia in the west to the Great Karoo. Temperature differences are great, 45 °C in summer, but it can survive in relatively low winter temperatures (-5 °C).
The plant appears to have a wide tolerance of growing habitats, growing in deep soils, on dry, stony slopes or flats and under the protection of karroid bushes.
Derivation of name and historical aspects
Euphorbia stellispina was discovered in 1685 when Governer Simon van der Stel and his expedition were camped out in Namaqualand near the present town of Springbok. One of the natural scientists in the party, Mr H. Claudis apparently found the plant.
The name, Euphorbia, comes from King Juba of North Africa, who dedicated the plant in honour of his doctor Euphorbus. The species name is Latin and is derived from stella, star, and spina, spine, and refers to the star-shaped arrangement of the spines.
Pollination is done mainly by bees and sometimes wasps. Euphorbia stellispina produces white latex sap which helps the plant to reduce transpiration, especially during the very hot summer months.
Uses and cultural aspects
Euphorbia stellispina is sometimes used by stock farmers in times of extreme drought. The spines are burnt by dragging a burning tyre over the plants. Once the thorns are burnt off, the stems are more accessible to livestock. E. stellispina is an excellent choice to have in a rock garden. They are strong architectural plants that make a definite statement.
Growing Euphorbia stellispina
This is can be done from cuttings or seed. Seeds can only be harvested when the capsule is light brown in colour. Due to the explosive nature of the seeds, one should place cottonwool over the seed capsules to stop them being blasted into the surrounding area. The soft cottonwool will effectively trap any seeds. Seeds are small, about 1 mm in diameter.
When sowing the seed, cover with a medium not deeper than 2-3 mm. Use a well-drained sowing medium of sandy loam with very well-rotted compost, and preferably sieved river sand to cover the seed. The ideal size of the sand grains should be 1 mm.
Move to a sunny (60% sun) well-ventilated location. Sow the seeds in March or April (southern hemisphere). By April of the following year, the plants should be strong enough to be planted in a small, 9 cm plastic pot.
Cuttings are relatively easy. The most important thing is to dry them out. This entails lowering the latex levels. Large cuttings, of 0.5 m or more need to be dried out for at least three weeks. Too much latex could rot the plant. Strike the cutting in coarse sand. The best time to strike cuttings are August, September and October (southern hemisphere).
Euphorbia stellispina grows easily and rapidly. The plants are not difficult to cultivate and look after. They also make ideal potplants and look very good in a ceramic pot in a courtyard.
- Rowley, G.D. 1987. Caudiciform and pachycaul succulents. Strawberry Press, California, USA.
Karoo Desert National Botanical Gardens