|DESCRIPTION: A deciduous, rigid, woody shrub, 1-2m tall, with stems typically branching in threes and terminating in spine-like tips. USE: It is a hardy species, rarely killed by intensive browsing or drought. Mismanagement and overgrazing initiate the multiplication of this species in areas which would otherwise be denuded of vegetation. In these situations it ensures a plant cover which protects the soil from wind and water erosion, provides sheltered sites for the establishment of seedlings and provides a reserve fodder bank in times of drought. Young roots are chewed for diarrhoea. GROWING PERIOD: Perennial. COMMON NAMES: Three-thorn, Kalahari soap bush. FURTHER INF: Indigenous to the arid western regions of southern Africa in Botswana, Namibia and the Northern Cape province of South Africa. An unpalatable species which is becoming increasingly invasive in arid rangelands as a result of overgrazing. Spreads very effectively by vegetative propagation. Prefers sandy and calcareous soils on plains, dune valleys and near pans and dry rivers. The distribution area of three-thorn falls within a summer rainfall area and the mean annual rainfall ranges from about 50mm in the south to about 350mm in the north-east. Rainfall is highly erratic, with a coefficient of variation of 54% and prolonged droughts are common. The wettest months are usually later in the summer, from January to April, when ambient temperatures and evaporative water losses are high.