Sekelbos, Klein-blaar Sekelbos
uGagane
Dichrostachys cinerea is a spiny, deciduous shrub or small tree typically up to 7 m high, but occasionally reaches 12 m.
It forms a rounded, wide crown and features strong alternate thorns (up to 8 cm long) that are hardened branchlets.
The leaves are bipinnate, resembling Acacia, with 4–19 pairs of pinnae and 9–41 pairs of leaflets.
The bicolored flower spikes (6–9cm long) are lilac/pale purple on top and yellow at the base. Flowers mainly between September and February.
It produces coiled, flat green pods that mature to brown, each with numerous seeds.
Bark is rough and fissured, typically yellow to grey-brown.
It is widespread in Africa, thriving in warm, dry savannas, grasslands, and disturbed areas. The species is highly adaptable and can colonize poor or disturbed soils, helping to stabilize and restore degraded land. It is this nature to colonize that results in its invasion of grasslands, forming dense, impenetrable thickets and outcompeting native grasses. Its invasiveness is especially triggered and accelerated by overgrazing. However, invasion also occurs in other situations, such as disturbed land, areas degraded by climate change, and unmanaged pastures.
Livestock: cattle, goats, and sheep consume pods, leaves, and young shoots.
Wild game: giraffe, buffalo, kudu, impala, nyala, klipspringer, monkeys, rhinoceros, bushpigs, and elephants all feed on various parts of the plant, especially pods and leaves.
Insects /Pollinators: bees are important pollinators, and the flowers are a valuable source for honey production. The pollen and nectar-rich flowers attract various ants, beetles, flies, and butterflies, making D. cinerea a hub for insect biodiversity.
Ecological Interactions: The plant’s fragrant flowers and nutritious pods not only support a variety of wildlife and insects but also enable seed dispersal through mammal and bird consumption. Its dense, thorny branches provide refuge and breeding sites for many invertebrates and birds, further integrating D. cinerea into its ecosystem.
Bicolored spikes (lilac/purple and yellow) attract bees and large carpenter bees (Xylocopa pubescens) as primary pollinators.
The flowers are insect-pollinated, rewarding visitors with a rich source of pollen and nectar.
Twisted pods are consumed by mammals that aid seed dispersal.
Fork-tailed drongo, bee-eaters, and various small birds are drawn to insect-rich flowers and also utilize the thorny branches for nesting sites.
The thorny shrubs provide nesting and cover for birds, attracting insectivorous species due to insect abundance.
Collect the pods once they have gone brown. Seeds need scarification to break dormancy and is best sown in sandy/loamy mix in spring. Germinates in 2–3 weeks at~25°C.
Be careful about where the shrubs are planted as, the absence of browsers that would usually control the growth of the shrubs, they have a high potential of becoming invasive.
Cuttings seldom succeed; propagation through seed and root suckers is preferred.
Historical Uses: Dichrostachys cinerea wood is valued for its strength and termite resistance, being used traditionally for fence posts, tool handles, walking sticks, and firewood, as well as for living fences. Its bark is important for fiber, weaving baskets, milk pots, and specialized smoking jars.
Medicinal Uses: Roots, bark, and leaves are used as a local anaesthetic for bites and toothache, for headaches, diarrhoea, and as a tapeworm cure in Botswana. Other reported uses include treating epilepsy, parasitic infections, rheumatism, and more in regional traditional medicine.
Pharmacological Action: Research supports the plant’s antimicrobial, anti-inflammatory, and anthelmintic activities, in line with its extensive use in folk medicine.
Bioactive Phytochemicals: Contains alkaloids, flavonoids, tannins, and other beneficial phytochemicals, contributing to its pharmacological properties.
Livestock: The plant is an important fodder resource during dry seasons; its pods are highly nutritious and sought after by livestock and various game species, while twigs and leaves also provide protein-rich forage.
Toxicity: No major toxicity is noted in livestock consuming D. cinerea pods and leaves; injuries are mainly caused by thorns, which can harm grazing animals and humans.
Soil and Nitrogen Fixation: As a legume, the species fixes nitrogen, thereby improving soil fertility and contributing to land reclamation, erosion control, and riverbank stabilization. It readily colonizes disturbed sites, curbing erosion quickly.
Caution: Dichrostachys cinerea often becomes invasive in areas where grazing pressure from livestock (grazers) is high and the density of browsing animals (browsers) is low or absent. Overgrazing by cattle and sheep removes grasses that would otherwise compete with D. cinerea seedlings, opening space and light for its establishment. In the absence of natural browsers that typically feed on young shoots and saplings, there is little to check dense thicket formation, leading to bush encroachment and invasive spread. Thus, ecosystems with an imbalance favoring grazers (or overgrazed systems without browsers) are particularly vulnerable to D. cinerea invasion.
