Dichrostachys cinerea is a spiny, deciduous shrub or small tree, up to 7 m high, with a rounded crown, 3 m wide. The bark is rough, yellow to grey-brown and frequently fissured and the stem is rarely thicker than 230 mm. The twice-compound, petiolate leaves are very variable in size with 4 to 19 pairs of pinnae and each pinna with 9 to 41 pairs of leaflets, giving it an Acacia-like appearance. The petioles (leaf stalks) are up to 50 mm long and the leaf length varies between 10 and 160 mm. The young twigs are slightly hairy and a characteristic feature is that the spines are not modified stipules but hardened branchlets, ending in a straight, sharp point.
The flowers are 25 to 50 mm long, pendulous spikes that are borne in the leaf axils, singly or in bundles. The pleasant-smelling fluffy flowers are lilac in the upper half and yellow in the lower, giving rise to the descriptive name Chinese lantern tree in other countries. Its flowering season is spring, generally from September to February.
Each flower produces a mass of flat, coiled green pods that turn brown and later fall to the ground. Each pod contains a large number of seeds; young pods are curved, resembling sickles.
Distribution and habitat
Dichrostachys cinerea is widespread throughout Africa. It also occurs in Madagascar, India, Indonesia and Australia. It occurs in a diverse range of habitats and is a conspicuous component of many plant communities. In southern Africa it is very common in the warm, dry savannas.
Dichrostachys cinerea is not threatened in any way.
Derivation of name and historical aspects
It is a very variable and taxonomically complex species. Two subspecies are currently recognized in southern Africa. Dichrostachys cinerea subsp. africana is small-leaved and subsp. nayassana is large-leaved. Within D. cinerea subsp. africana, two varieties are recognized, based on the hairiness of the leaves.
The genus name is derived from the Greek, dis, meaning two; chroos, meaning colour; and stachys, meaning spike. The species name cinerea means grey-haired, referring to the hairs on the typical species in India. The genus contains approximately 20 species indigenous to the tropics of the Old World, from Africa to Australia; a good proportion of the species are indigenous to Madagascar.
Dichrostachys cinerea is a nitrogen-fixing legume and therefore has a positive effect on the nitrogen content of the soil. It has the ability to colonize disturbed veld quickly and curbs erosion. The pods are very nutritious to animals and are eaten by stock and game, including monkeys, rhinoceros and bushpigs.
It sometimes forms impenetrable thickets and becomes a problem plant for veld managers. It was introduced to the West Indies during the 19th century, where it has invaded range lands and caused significant economic losses in agricultural production. It is important that propagules of this species do not reach areas of similar climates, such as Hawaii or South America, where risk assessments have indicated a high chance of invasiveness.
Uses and cultural aspects
Dichrostachys cinerea makes impressive bonsai specimens. The hard and durable wood is also termite resistant, making it ideal for fence posts. It is also used to make tool handles, milk pots, smoking jars, and fibre from the bark. It is often planted to serve as live fencing and as a fodder. The roots are used as a local anaesthetic for ailments such as snake bites, scorpion stings and toothache. In Botswana, parts of the tree are used as a tapeworm cure. It also makes high quality firewood.
Growing Dichrostachys cinerea
It requires little water and full sun; mature plants can withstand moderate frost, but young plants must be protected from frost. It grows fairly quickly and requires frequent pruning to keep it neat. Due to its size and very thorny nature, it is not suited to small gardens.
It produces copious amounts of seeds which germinate readily. Immerse the seeds in hot water, allow them to cool and then soak in water for 24 hours. The ideal sowing medium is coarse sand or soil that is mixed 1 part soil to 3 parts compost, to promote proper drainage. Plant the seeds to a depth equal to their diameter. Seedlings appear within 2 to 10 days. It can also be propagated from cuttings.
References and further reading
- Bein E., Habte B., Jaber A., Birnie A. & Tengnäs B. 1996. Useful trees and shrubs in Eritrea : identification, propagation and management for agricultural and pastoral communities. Regional Soil Conservation Unit, Nairobi.
- Carr, J.D. 1994. The propagation and cultivation of indigenous trees and shrubs on the highveld. Sandton Nature Conservation Society and the Tree Society of South Africa, Johannesburg.
- Coates Palgrave, M. 2003. Keith Coates Palgrave Trees of southern Africa, edn 3. Struik, Cape Town.
- Glen, H.F. 2004. SAPPI What's in a name? The meaning of the botanical names of trees. Jacana, Johannesburg.
- Joffe, P. 1993. The gardener's guide to South African plants. Tafelberg, Cape Town.
- Palmer, E. & Pitman, N. 1972. Trees of southern Africa covering all known indigenous species in the Republic of South Africa, South-West Africa, Botswana, Lesotho and Swaziland, vol. 2. Balkema, Cape Town.
- Ross, J.H. 1974. A note on Dichrostachys cinerea. Bothalia 11: 265–268.
- Ross, J.H. 1975. Dichrostachys. Flora of southern Africa. 16,1: 123–129.
- Schmidt E., Lötter M. & McCleland W. 2002. The trees and shrubs of Mpumalanga and Kruger National Park. Jacana, Johannesburg.
- website: http://www.hear.org/pier/species/dichrostachys_cinerea.htm (accessed 14-08-2009).
- website: http://www.issg.org/database/species/ecology.asp?si=161&fr=1&sts (accessed 14-08-2009).
- website: http://www.up.ac.za/academic/botany/garden/species/119.html (accessed 14-08-2009).
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