There is no doubt that this is an excellent tree to use in a landscape, and it is a rewarding garden tree. It gives shade in summer, and is fast and easy to grow under a wide range of conditions.

Description
This beautiful deciduous tree grows up to 25 m tall in a forest habitat, but in a garden it can be treated as a medium-sized tree, expected to reach a height of up to 12 m. In the wild, where it is growing in an exposed, rocky position it may be nothing more than a shrub,but well-grown specimens will have a single, straight bole branching to form a dense, semi-circular canopy. The trunk of Celtis africana is easy to distinguish by its smooth, pale grey to white bark. It may be loosely peeling in old trees and sometimes has horizontal ridges.

In spring Celtis africana is very lovely, with its light green, tender, new leaves that contrast beautifully with the pale bark. The leaves are simple, alternate, triangular in shape with three distinct veins from the base, and the margin is toothed for the upper two-thirds. The new leaves are bright, fresh green and hairy, and they turn darker green and become smoother as they mature. Celtis africana leaves are browsed by cattle and goats, and are food for the larvae of the long-nosed butterfly.

The flowers appear in spring (August to October). They are small, greenish, star-like and inconspicuous. Separate male and female flowers are produced on the same tree.A cluster of male flowers is borne at the base of the new leaf, and the female or bisexual flowers are in the axils of the leaves. The flowers are pollinated by bees. Masses of small, rounded, berry-like fruits on 13 mm long stalks follow the flowers, from October to February. When they turn yellow-brown to black they are ripe. Many birds like rameron pigeons, willow warblers, black-eyed bulbuls, mousebirds and crested barbets feed on the fruits and disperse the seeds.

Distribution
Celtis africana is common and widespread in South Africa. It occurs in a wide range of habitats from the coast up to 2 100 m, from the Cape Peninsula northwards through South Africa to Ethiopia, where it grows in dense forest, on rocky outcrops, in bushveld, in open grassland, on mountain slopes, on coastal dunes, and along river banks and in kloofs.

Derivation of the name
The genus name Celtis is the Latin name used by Pliny, and is also the ancient Greek name for one of the plants reputed to be the lotus of the ancients. The specific epithet africana means African. Celtis africana thus means, the African celtis. C. africana is commonly known as white stinkwood, because of the unpleasant smell of the freshly cut wood, and it's pale colour. The timber of C. africana has no commercial value. It is very unfortunate that it has this common name as it causes confusion with the true stinkwood, Ocotea bullata. These two species do not look similar, nor are they closely related. Ocotea bullata belongs in the laurel family (Lauraceae).

The genus Celtis contains about 50 species widely spread throughout the warm temperate regions of the world. Only three species are indigenous to southern Africa namely Celtis gomphophylla (false white stinkwood), C. mildbraedii (Natal white stinkwood) and C. africana. In southern Africa there are 5 species in this family, the three Celtis species, Trema orientalis (trema/pigeon wood) and Chaetachme aristata (chaetachme/false white pear). This family is closely related to the elm family Ulmaceae, which is distributed mainly in the north temperate regions of the world.

Celtis africana closely resembles, and can be easily confused with Trema orientalis. Trema is not as widely distributed, nor as tolerant of tough conditions as C. africana. Also, trema leaves tend to be larger and more slender, serrated nearly from the base, and the female flowers and fruits are carried on much shorter stalks than those of C. africana. Furthermore, related exotic species, C. australis (nettle tree), C. sinensis (Chinese hackberry) and Ulmus parvifolia (Chinese elm), are cultivated in gardens in South Africa and do occasionally escape into natural areas where they may be confused with the indigenous species.

Uses and cultural aspects
The wood of Celtis africana is white to yellowish in colour and of medium hardness. It is tough and strong, and polishes well, but is difficult to work. It is a good general timber suitable for making planks, shelving, yokes, tent-bows and furniture. The African people have always used it to make a variety of household articles. It is also thought to have magical properties. The wood is mixed with crocodile fat as a charm against lightning, and many people believe that it has the power over evil and that pegs of wood driven into the ground will keep witches away.

Growing Celtis africana

Celtis africana is fast and easy to grow. It is fairly drought resistant and can withstand frost. It does best in good, rich, deep soil with plenty of water in summer. This is an excellent tree for large gardens and parks, and has also proved to be a successful street and avenue tree. At Kirstenbosch they were planted in the new Visitors' Centre car park where in a short space of time they are already providing shade and softening the hard, hot expanse of paving. In the garden, it makes an ideal shade tree, particularly when planted on the northern or western side of the house, where the shade provided cools the house in summer, yet allows the sun through to heat the house in winter. It also works well as a specimen plant in a tub in a courtyard garden, and makes a beautiful bonsai subject.

Freshly collected seed germinates easily. Seeds collected from the ground are usually infested by insects, so it is best to harvest from the tree. The flesh from the berry is best cleaned off and the seeds should be sown in a flat seedling tray filled with river sand and well decomposed compost (5 parts river sand to 1 part compost). The seeds should be covered with a thin layer of river sand and kept moist. The trays should be placed in a warm but shaded area. Germination will take 15 to 30 days with an expected germination of 70%. Transplant the seedlings into good, rich soil and give them plenty of water and they will grow fairly fast, putting on 1 to 2 m per year.

References.

• Germishuizen, G., Meyer, N.L., Steenkamp, Y. & Keith, M. (eds) 2006. A Checklist of South African plants. Southern African Botanical Diversity Network Report No. 41. SABONET, Pretoria.
• DE WINTER, B., DE WINTER, M. & KILLICK, D.J.B. 1966. Sixty six Transvaal trees. Botanical Research Institute, Pretoria.
• PALMER, E. & PITMAN, N. Trees of southern Africa. Balkema, Cape Town
• VENTER. F. 1993. Making the most of indigenous trees 50. Farmers Weekly, 5 November: Page 65.
• VERDOORN, I.C. 1956. Celtis africana. The Flowering Plants of Africa 31: t. 1210.
• TRENDLER, R. 2000. White Stinkwood.Urban Green File, May/June 2000, Page 19
• LEISTNER, O.A. (ed.). 2000. Seed plants of southern Africa: families and genera. Strelitzia 10. National Botanical Institute, Pretoria.
• GRANT, R. & THOMAS, V. 2000. Sappi tree spotting: Bushveld. Jacana, Johannesburg.
• COATES PALGRAVE, K. 1977. Trees of southern Africa, edn 1. Struik, Cape Town, Johannesburg.
• JACKSON, W.P.U. 1990. Origins and meanings of names of South African plant genera. UCT Printing Department, Cape Town.
• HEYWOOD,V. H., BRUMMITT, R.K., CULHAM, A. & SEBERG, O. 2007. Flowering plant families of the world. Firefly books Ltd, Ontario,Canada.

Giles Mbambezeli & Alice Notten
Kirstenbosch National Botanical Garden
January 2003
Updated July 2008