Publication: Bothalia 6: 222 1951
Description
Euphorbia confinalis is an elegant, spiny, succulent-tree. The epithet “confinalis”(Latin: confine/is = on the border) in the species’ name refers to the fact that its distribution, broadly coincides with the border between South Africa and neighbouring countries.
Habit:It is a slender, single-stemmed, leafless candelabra-shaped tree, often with secondary stems along main trunk; with a round canopy of upward-growing branches, 3-10 m tall.
Stems: Trunk single erect but sometimes branched, each large branch with a crown of curved, ascending individual branches forming many side, branchlets originating at the same level. Branchlets usually with 4 wings (sometimes 3-5), 60-70 mm in diameter, pale green to blue-green, usually constricted into long rectangular segments with parallel sides.
Spine shields: Conspicuous, horny and usually separate along each ridge.
Spines: Simple, paired, slender, 5-7 mm long.
Flowers: Small and pale yellow, just above the spines on the ridges; in groups of 3, the middle one male and the other 2 bisexual.
Blooming season: Late autumn to winter (May-Aug).
Fruit: 3-chambered capsule, round 8-10 mm in diameter on a long stalk, ripening to wine-red and splitting open when mature (July-Oct).
Similar species: Euphorbia zoutpansbergensis is a more graceful plant with branches 6-angled and much more slender (20-35 mm in diameter) and is endemic to the Soutopansberg region. Euphorbia sekukuniensis from the Steelpoort River Valley and adjacent areas, has 4- or 5- angled, slightly constricted branches which are even more slender (15-20 mm in diameter), with a continuous horny strip along each margin. Euphorbia confinalis is also easily confused with Euphorbia triangularis; the latter appearing less robust and more winged.
Origin and Habitat
South Africa (Lebombo Mountains form the eastern boundary of the Kruger National Park, from as far north as Shingwedzi) also Swaziland, well into northern KwaZulu-Natal, southern Mozambique, Limpopo Province and south-eastern Zimbabwe.
Altitude: It occurs at low altitudes, the average altitude varies between 300 and 400 metres above sea level.
Habitat: It grows widespread in deciduous woodland in a mountainous area with many of the large west-east rivers forming deep gorges, usually on volcanic rhyolite outcrops on rocky slopes and ridges, sometimes in riverine vegetation on deep alluvial soil or in savanna. The rainfall increases southwards from 400 mm in the north, to 700 mm on the south.
Cultivation and Propagation
Euphorbia confinalis is another easy plant to grow.
Growth rate: It grows well, though slowly, but it possible to increase the speed of growth to some extent by providing adequate amount of water, warmth, and a liquid fertilizer diluted half strength during the active growing season, but it’s susceptible to rotting if too wet. Large trees can be produced in a few years.
Soil: Likes porous sub-acidic substrata (pH 6) with adequate drainage. Outdoors it does well on poor, rocky soils.
Exposure: Need bright light (also blasting sun in summer) to partial shade for best appearance. It responds well to warmth, with its active growth period in the late spring and summer months. If grown indoor provide 4 to 6 hours, or more, direct morning or afternoon sun.
Watering: Water thoroughly when soil is dry to the touch during active growing season (more than once a week during hot weather) In the winter months, waterigs should be suspended or restricted to once over the winter. The most common failure in growing this plant is over watering, especially during the winter months.
Hardiness: Very tender, protect from frost. During winter month, put them in a cool luminous place and encourage them to enter winter dormancy by withholding water and fertiliser over the winter as they will etiolate, or become thin, due to lower levels of light.
Maintenance: Repot every two years. Needs lots and lots of space to grow, use large shallow container filled with very porous compost. It like pots with generous drain holes.
Reproduction: It is propagated by cuttings or seeds. The seeds may be germinated and grown in containers. Their main requirements consist of high humidity levels, free-draining soil mix, and enough water, light, and nutrition. It is recommend taking Euphorbia cuttings in Spring/Summer when the plant is growing so that they have a better chance of success. They key is heat & good air circulation. These cuttings should be dipped in Hormone powder (but it is not needed) and left for a period of 3-4 weeks to callous. Then pot the cutting and don’t water ( or kept slightly moist) until rooted. These will root just fine, if you can put the pot outside in the summer, or put pot on a heating pad.
Warning: As with all other Euphorbias when a plant get damaged it exudes a thick white milky sap known as latex. This latex is poisonous and particularly dangerous for the eyes, skin and mucous membranes. So pay extreme attention not to get any in your eyes or mouth. Cultivated plants must be handled carefully.
Notes
Although Euphorbia confinalis bears a striking resemblance to some American cacti, they are in no way related. The similarity is merely a striking example of how plants that live in different areas but are faced with similar environments evolve similar growth forms (convergent evolution). In this case the challenge of aridity has resulted in the loss of leaves, with the stems becoming green and photosynthetic in their place. This adaptation helps the plants to conserve water.
Bibliography
Major references and further lectures
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Ernst Schmidt, Mervyn Lötter, Warren McCleland “Trees and Shrubs of Mpumalanga and Kruger National Park” Jacana Media, 01/gen/2002
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Eve Palmer, Norah Pitman “Trees of Southern Africa, covering all known indigenous species in the Republic of South Africa, South-West Africa, Botswana, Lesotho & Swaziland , Volume 2” A. A. Balkema, 1972
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Urs Eggli “Illustrated Handbook of Succulent Plants: Dicotyledons” Springer, 2002
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Hermann Jacobsen “A handbook of succulent plalnts: Abromeitiella to Euphorbia” Blandford Press, 1960
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Jacana Maps “SAPPI Tree Spotting – Lowveld including Kruger National Park” Jacana Media, 2006
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N. Dennis, Bob Scholes, Nigel Dennis “Kruger National Park: Wonders of an African Eden” Struik, 01/mar/2006
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Vincent Carruthers “The Wildlife of Southern Africa: A Field Guide to the Animals and Plants of the Region” Struik, 01/mar/2005
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Braam Van Wyk, Piet Van Wyk “Field Guide to Trees of Southern Africa” Struik, 1997