A fine, fast-growing tree for sheltered gardens, easily raised from seed and an unusually decorative tree for larger gardens and parks.
Rauvolfia caffra is an evergreen tree up to 30 m tall with a roundish crown. The main stem is straight, tall, and bare. Bark is grey to brown, rough with prominent leaf scars on younger branches, becoming yellowish brown, thinly corky and cracked into small squares with age. Leaves simple, in whorls of 3–6, crowded at the ends of the branchlets, slightly leathery, tapering to both ends, about 120–280 mm long and 30–60 mm broad. Leaf blade shiny green above, paler green below with midrib raised and margins smooth. Leaf stalk up to 35 mm long.
||Left: Rauvolfia caffra flowers
Right: Rauvolfia caffra fruit
Flowers in R. caffra are produced in terminal sprays at ends of branches, small, about 4 mm long, white, waxy and sweetly scented, with dense hairs at mouth of flower tube. Flowering time is from May to October. Fruits are in large branched clusters, fleshy, almost spherical, 1- or 2-locular, shiny dark green with white spots, turning black and wrinkled when mature. Fruiting time is from October to March.
The IUCN Red List status for Rauvolfia caffra is Least Concern because, being a protected tree in South Africa, it is not over-exploited commercially (see the uses below).
Distribution and habitat
Rauvolfia is a genus of about 60 species; seven of these are found in Africa, three in Madagascar and one is confined to southern Africa.
Rauvolfia caffra is restricted to coastal forests in east, central and southern Africa. The species occurs in seven provinces in South Africa and in Swaziland. In South Africa, it is found along the coastal belt, in the eastern regions of South Africa, from the Eastern Cape to KwaZulu-Natal, extending further north and inland to Mpumalanga, Limpopo, Gauteng and North-West. Rauvolfia caffra occurs at an altitude from 0 to about 1 500 m on sandy and loamy soils. It is usually found along wooded streams, on river banks, at margins of evergreen forest and in swamp forest where it can reach up to 30 m in height. When growing away from rivers and streams the species is always associated with available ground water, and is therefore regarded as an indicator of water, and classified as a hydrophyte.
Derivation of name and historical aspects
‘Rauvolfia' was named after a medical doctor and a collector of drug plants from the 16th century, Leonhart Rauwolf of Augsburg, and 'caffra' means 'of Kaffraria' (Eastern Cape). The common name 'quinine tree' refers to the bitter and supposedly quinine-like properties of the bark.
The sweetly scented flowers attract butterflies and other insects, which in turn attract insect-eating birds, that bring about pollination. The hydrophilic nature of the plant allows seed dispersal by water to take place.
Uses and cultural aspects
Rauvolfia caffra is of economic value. The plant is a very decorative neat shade tree and is suitable for larger gardens and parks. The wood is used for drums, general timber work on the farm, making of fruit boxes, and is ideal for kitchen furniture and shelving.
||Rauvolfia caffra trunk peeled
The bark is used as a dressing for wounds and the infusion is used to kill maggots in wounds. Pieces of bark are chewed to treat coughs. The latex is used to treat diarrhoea and other stomach ailments. The latex contains alkaloids that are used in preparations for the treatment of high blood pressure and certain mental aberrations. The leaves, flowers and fruits serve as the source of food to vervet monkeys.
Growing Rauvolfia caffra
The tree is easily propagated from seed, transplants well and is comparatively fast-growing, with a growth rate of up to 1.5 m per year.
The pulp must be removed from the fruit, washed with water and sown in seedling trays filled with a mixture of river sand and compost. The seeds should be pressed into the mixture until they are flush with the surface. The seedlings should be transplanted into nursery bags when reaching the 3-leaf stage. Seedlings and young plants transplant well when given sufficient water for the first three months until they are established.
Young plants should be placed in good fertile soil that contains plenty of compost, in moist areas. The species is not resistant to cold and thus cannot cope with odd frost conditions.
References and further reading
- Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of southern Africa, edn 3. Struik, Cape Town.
- Leistner, O.A. 2005. Seed plants of southern tropical Africa: families and genera. Southern African Botanical Diversity Network Report No. 26. SABONET, Pretoria.
- Pooley, E. 2003. The complete field guide to trees of Natal, Zululand & Transkei. Natal Flora Publications Trust, Durban.
- Raimondo, D., Von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. & Manyama, P.A. (eds) 2009. Red List of South African plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
- Van Wyk, A.E.& van Wyk, P. 1997. Field guide to trees of southern Africa. Struik, Cape Town.
- Van Wyk, P. 1974. Trees of the Kruger National Park. Purnell & Sons, Cape Town.
- Venter, F. & Venter, J. 1996. Making the most of indigenous trees. Briza Publications, Pretoria.