Euphorbia nesemannii R.A.Dyer
Common names: Nesemann's euphorbia (Eng.); melkpol (Afr.)
A spiny, tuberous rooted species with a nearly cylindrical body, most of which is below the ground.
Euphorbia nesemannii is a spiny succulent shrublet with tuberous roots, a partly subterranean body and subcylindrical stems that are strongly 6–14-angled. It produces 4 or more ascending branches, each 10–30 mm in diameter and its spines are relatively weak and blunt, but may be up to 25 mm long and tubercles are absent on older branches. The stems may be only 100 mm tall in stony habitats, but can exceed 600 mm in older plants, in deeper soils, or in the shade.
The flowers are yellow and appear between late autumn and mid-winter. The fruits are dark brown to black.
According to the Red List of South African plants website, the conservation status of this plant is Near Threatened (NT). The wild population is declining because of habitat loss caused by agriculture and limestone mining.
Distribution and habitat
Euphorbia nesemannii is endemic to South Africa, and is found only in the lower Breede River Valley of the Western Cape, from Worcester and McGregor in the west, to Swellendam in the east. It grows in full sun on footslopes, where there is rich, well-drained soil.
Derivation of name and historical aspects
Euphorbia nesemannii was discovered by A. Nesemann in 1930, near Robertson and the species was then named after him by Dr Dyer. The genus name Euphorbia derives from Euphorbus, the Greek physician of King Juba II of Numidia (52–50 BC to 23 AD), who married the daughter of Anthony and Cleopatra.
Euphorbias are commonly called spurges, which is derived from a Latin word expurgare, which means ‘to purge’, ‘cleanse’ or ‘to purify’, a reference to the toxic nature of the white latex that many of the species possess. The Euphorbiaceae is one of the largest and most diverse families of flowering plants in the world, with more than 2 000 species, and is particularly diverse in Africa, Arabia and South America.
The species grows in an arid area of winter rainfall (about 200 mm per year), with hot, dry summers. Soils in the area are typically clay-rich and are derived from shales, but the species may also be found in quartzite outcrops within the shale landscape. Porcupines are known to eat the plants during the dry summers. The flowers are pollinated by generalist flies.
Euphorbia nesemannii is not often used and is poorly known in cultivation, but should be valued for its ability to survive under hot and dry conditions, and for its attractive growth form.
Growing Euphorbia nesemannii
Euphorbia nesemannii can be propagated both by seeds and cuttings. Water the trays with fungicide to reduce damping off, and sow seeds in spring. For stem cuttings, allow the wounds to dry and form a callus. Plant in a well-drained soil and place the tray in a cool area with diffuse light. No regular watering is required, but water once after planting, then once after it has rooted, and soils should be well drained. Slowly expose the plant to more sun to encourage more growth.
This plant is suited for a rockery, in the arid winter rainfall area, planted together with Pelargonium alternans (koolmalva), Brianthuntleya intrusa, Tylecodon paniculatus (butter tree), Drosanthemum speciosum (Worcester Robertson vygie) with their bright showy red flowers, Othonna arbuscula (traap) and Cotyledon orbiculata (pig's ears), will complement one another.
- Brewerton, D.V. 1968. Two Rarely Seen Euphorbias. Cactus and Succulent Journal of Great Britain. 30(1): 6
- Court, D. 1981. Succulent flora of southern Africa. Balkema, Cape Town.
- Dyer, R.A. 1935. Bulletin of Miscellaneous Information Kew 1934. Pp. 267, 268.
- Helme, N.A., Van Jaarsveld, E.J. & Raimondo, D. 2007. Euphorbia nesemannii R.A.Dyer. National Assessment: Red List of South African plants version 2017.1. Accessed on 2018/04/24.
Karoo Desert National Botanical Garden
Acknowledgements: The author thanks Nick Helme for assistance with information for this article.
Plant Type: Shrub, Succulent
SA Distribution: Western Cape
Soil type: Sandy, Loam
Flowering season: Autumn, Winter
PH: Acid, Neutral
Flower colour: Yellow
Aspect: Full Sun
Gardening skill: Easy