Euphorbia triangularis Desf. ex A.Berger
Common names: river euphorbia, chandelier-tree, tree euphorbia (Eng.); riviernaboom (Afr.); umhlonthlo (isiXhosa); umhlonhlowane, isiphapha (IsiZulu)
SA Tree No: 356
A spiny, succulent tree with angled, segmented branches that leak a watery milky latex when damaged; it belongs in the spurge family, one of the largest plant families.
A spiny, succulent tree 2.5–10 m, up to 18 m tall, with a yellowish green, candelabra-like crown. E. triangularis has a single, rounded, slightly angled stem and grey bark. Branchlets appear wing-like because they are either 3- or 5-angled. Trees with 3-angled branchlets are mostly common in Eastern Cape and the 5-angled ones are found mostly in KwaZulu-Natal. The branchlets are 40–90 mm in diameter and 50–500 mm long, with parallel sides and somewhat wavy margins.
E. triangularis has spines that are paired, up to 8 mm long, and are borne on separate shields or on continuous horny cushions along the margins. Flowers in clusters, greenish yellow, in winter (Jun. –Aug.).
Fruit a globe-like capsule, 6–8 mm in diameter, distinctly stalked, reddish, in winter–spring (Jul. –Oct.).
According to the Red List of South African plants, Euphorbia triangularis is assessed as Least Concern (LC).
Distribution and habitat
Found growing in dense stands in the Eastern Cape, KwaZulu-Natal and Mpumalanga, and also in Mozambique, in river valleys, on dry, rocky hillsides and clayey slopes of river valleys, in open dry woodland, bush thicket and bushveld, often just above coastal rivers, mainly at lower altitudes up to 1 665 m above sea level.
Derivation of name and historical aspects
Euphorbiaceae is the name given to one of the largest plant families in the plant world, commonly called spurges. The family Euphorbiaceae includes around 300 genera and 7 500 species, and of these around 870 are regarded as succulent.
The name Euphorbia is derived from Euphorbus, the Greek physician of King Juba II of Numidia (52–50 BC–23 AD), who married the daughter of Anthony and Cleopatra. Juba was a prolific writer on various subjects, including natural history. Euphorbus wrote about how one of the cactus-like euphorbias, now called Euphorbia obtusifolia subsp. regis-jubae, was used as powerful laxative. In 12 BC, Juba named this plant after his physician Euphorbus. In 1753, botanist and taxonomist Carl Linnaeus assigned the name Euphorbia to the entire genus in the physician’s honour. Triangularis means ‘three-angled’.
Flowers of Euphorbia triangularis attract butterflies, bees and other insects. Fertilized flowers form seed capsules. When the fruits are ripe, the capsules dry, and split open to release the seeds. The seeds are dispersed by the explosive action of the seed capsules and are banked in the soil during the dry winter season. The seeds germinate in the summer rainfall season. This species has succulent stems and branchlets, which store water to allow the plant to survive the dry winter season and its shallow root system makes it more adaptable for growing in rocky areas and shallow soil.
In Pondoland this tree is known as the tree of twins. When twins are born, two saplings are planted behind the homestead and the babies’ bath water is used to water the two trees. A special relationship is believed to exist between the twins and their trees, and the development of the trees is believed to mirror that of the children and indicate their state of health. If one becomes sick, their tree’s roots are used to make a body wash. If either twin dies, their tree is removed.
This tree is respected and admired by Xhosa people, so much so that if someone damages a tree and it oozes its characteristic milky sap, the person must give the tree a few white beads, or a silver coin, as a gesture of apology.
In traditional Zulu culture, these trees are burned on the fields to ensure a good crop.
Growing Euphorbia triangularis
Euphorbia triangularis grows quite easily from seeds sown in spring or summer, in a well-drained sowing medium, in pots or trays, placed under cover, in a warm spot and kept moist. Another quick and easy method is to gather up the seedlings from around an established plant. Take care not to damage the developing roots while digging them up. Take stem cuttings and root them in a soilless medium, such as peat. Keep them lightly misted in a mist unit, or enclose the pot in a clear bag to keep moisture in. Let the pot breathe once a day for an hour, so the soil does not grow mould. Seedlings or rooted cuttings should be planted in well-drained soil in a sunny position. Add compost to the soil and mulch well to retain moisture. Give them moderate water. Always ensure that safety measures are taken and caution is exercised when propagating these plants, to prevent the milky latex from coming into contact with your skin or eyes, while pruning or potting the plant.
E. triangularis is best used as an ornamental form plant or as a focal feature in a garden situation, and looks spectacular if planted with succulent ground cover plants. It can even thrive in very poor soils and can tolerate periods of drought, but will perform best if provided with light to moderate moisture. It is also suitable for containers.
If given ample water, this Euphorbia will bush out and grow faster. If you want a more natural looking, tree-like plant, keep it very dry and it will grow up rather than out, but rather slowly.
Watch for annoying pests like White Fly.
- Archer, R.H. & Victor, J.E. 2005. Euphorbia triangularis Desf. National Assessment: Red List of South African plants version 2017.1. Accessed on 2018/09/04
- Boon, R. 2010. Pooley's trees of eastern South Africa, a complete guide. Flora & Fauna Publications Trust, Durban.
- Khumbula Indigenous Garden website: Euphorbia triangularis. https://kumbulanursery.co.za/plants/euphorbia-triangularis, accessed 31 July 2018
- Mgcuwa, S. 2017. A tree perfect for the novice gardener. Grocott’s Mail, Local and lovely. 15 August 2017. http://www.grocotts.co.za/2017/08/15/euphorbia-triangularis-needs-a-headline/#prettyPhoto
- Pooley, E. 1998. A field guide to wild flowers Kwazulu-Natal and the eastern region. Natal Flora Publications Trust, Durban.
- Van Wyk, A.E. (Braam) & Van Wyk, P. 2013. Field guide to trees of southern Africa, edn 2. Struik, Cape Town.
- Zukulu, S., Dold, T., Abbott, T. & Raimondo, D. 2012. Medicinal and charm plants of Pondoland. South African National Biodiversity Institute, Pretoria.
KwaZulu-Natal National Botanical Garden
Plant Type: Tree
SA Distribution: Eastern Cape, KwaZulu-Natal, Mpumalanga
Soil type: Clay, Loam
Flowering season: Spring, Winter
Flower colour: Yellow
Aspect: Full Sun
Gardening skill: Easy