Local names:
Arabic (umm ageda,godem,gaddein,gaddeim), Hindi (gangu kanger,gango,gangerun,achchu), Somali (duferu,dekah,defarur,damak), Wolof (kel)
Grewia tenax is a multistemmed shrub up to 2 m tall, usually rounded but generally battered and untidy due to browsing. Bark smooth, grey, very fibrous so that twigs are hard to break. Leaves alternate, almost circular in outline, 1.5-4 cm in diameter, margins toothed and prominently tri-nerved at the base, often hairy, particularly beneath with star shaped hairs. Stipules inconspicuous, falling early. Flowers solitary or in pairs, axillarily placed, petals white, about 1 cm long; sepals long and recurved. Fruit orange-red at maturity, with 1-4 spheroid lobes. Grewia tembensis and G. tenax are virtually indistinguishable in fruit. The specific epithet refers to the plant’s tenacious growth habit. The genus was named after Nehemiah Grew (1641-1712), one of the founders of plant physiology.
Ecology
G. tenax is highly drought resistant and occurs in the driest savannas at desert margins and regions of higher rainfall, where it grows in thickets on termite mounds in otherwise seasonally flooded country. In the Sahel it grows in rocky places on hills and slopes, in regions with 100-600 mm of rain per annum.
Native range
Algeria, Botswana, Chad, Djibouti, Ethiopia, Iran, Kenya, Mali, Mauritania, Morocco, Namibia, Niger, Nigeria, Saudi Arabia, Senegal, Somalia, South Africa, Sudan, Tanzania, Uganda, Zimbabwe
Tree management
The shrub is drought tolerant, an adaptation to the erratic rainfall in its natural habitat. Seedlings survive planting out with ease, but never grow large. Growth is fast, sometimes up to 1.5 m in 8 months. Plants need protection from browsing animals. Total nursery time for G. tenax is approximately 2 months.
Germination is reportedly difficult in this species, however, germination percentages of over 75% have been achieved by pretreating seed by repeated washing and scrubbing until all flesh is removed. Germination occurs after 10 days. There are 15 000-21 000 seeds /kg.
G. tenax is highly drought resistant and occurs in the driest savannas at desert margins and regions of higher rainfall, where it grows in thickets on termite mounds in otherwise seasonally flooded country. In the Sahel it grows in rocky places on hills and slopes, in regions with 100-600 mm of rain per annum.
Direct sowing is a preferred propagation method. Depulped seed is sown in pots which are initially placed under shaded conditions but exposed to direct sunlight after 1 month.
Poison: A mucilaginous bark preparation is used by women against hair vermin.
With regard to its sturdy growth habit, G. tenax seems promising as a dune fixing plant in desert reclamation.
Erosion control: G. tenax has an aggressive root system which holds fast to the soil protecting it from water and wind erosion.
The fruits consumed by man and animals contain a large amount of iron and can be made into a refreshing drink. Fruit storage can be extended by drying. The dead leaves are eaten, but only while they remain on the plant.
Fodder: Young leaves are consumed by livestock, they are slightly palatable at the end of dry seasons, and have fairly good feed value.
Apiculture: Bees visit the flowers for pollen and nectar.
The branches are used as firewood, and can be used in charcoal making.
Fiber: The bark is used to make ropes and for binding purposes in house construction.
Timber: G. tenax wood is used in making weapons such as clubs, bows, arrows and for other general purposes.
Medicine: In Kenya plant parts are used as a remedy for colds and chest complaints and also as a chief constituent in a typhoid remedy.
The shrub can be used for hedging.
Soil improver: Leaf litter from the shrub improves soil physical and chemical properties.
Intercropping: Intercropping with G. tenax may not affect crop growth adversely.