Vachellia is a genus of flowering plants in the legume family, Fabaceae, commonly known as thorn trees or acacias. It belongs to the subfamily Mimosoideae. Its species were considered members of genus Acacia until 2009. Vachellia can be distinguished from other acacias by its capitate inflorescences and spinescent stipules. Before discovery of the New World, Europeans in the Mediterranean region were familiar with several species of Vachellia, which they knew as sources of medicine, and had names for them that they inherited from the Greeks and Romans. The wide-ranging genus occurs in a variety of open, tropical to subtropical habitats, and is locally dominant. In parts of Africa, Vachellia species are shaped progressively by grazing animals of increasing size and height, such as gazelle, gerenuk and giraffe. The genus in Africa has thus developed thorns in defence against such herbivory. The members of Vachellia are trees or shrubs, sometimes climbing, and are always armed. Of the 163 species currently assigned to Vachellia, 52 are native to the Americas, 83 to Africa, Madagascar and the Mascarene Islands, 32 to Asia and 9 to Australia and the Pacific Islands.

Vachellia kosiensis, synonymously known as Acacia kosiensis and commonly known as Dune Thorn in English, Duinesoetdoring in Afrikaans or uMunga in isiZulu, is a quick-growing, handsome tree that attracts many birds, bees and other insects and even bushbabies to the garden; it is also a useful barrier plant and is ideal for coastal gardens, and the wood makes excellent charcoal for the braai. Vachellia kosiensis is a South African endemic species found in the KwaZulu-Natal province. The bright yellow, pompon flowers are sweet scented and rich in nectar, making it a great tree for bees and butterflies. The roots of these trees produce nitrogen manufactured by the bacteria in the nodules, helping to increase soil fertility, and thus stronger plants of other species growing near them. A tall, upright tree, 10 to 17 m, with a spreading crown. Stems are pale, greyish white, with shallow, red-lined fissures in the bark.

In a garden situation, use this tree’s survival skills to the full, by planting groves around your boundary fence, to help ward off marauders, both human and browsing. The thorns on this species are very effective barriers to animals, including us humans. This tree’s wood makes a fine firewood and produces a wonderful set of coals for cooking. It can also be used to make fence posts, poles, yokes and furniture.

The gum, which exudes from wounds in the bark, is edible and sweet tasting. It can be used as a sweetener and coagulant in confectionary.
Used in landscaping, it makes a good street tree, although plant it at least 3–4 m away from the kerb edge, or paving, as the roots have the habit of lifting paving or road tar. The most prevalent use of this species is as a pioneer tree for sand dune reclamation after mining of sand dunes in the Richard’s Bay region.

A mixed grove of different acacias in a garden, makes for a garden full of birds and insects. Acacia Veld is one of the most productive habitats that you can have from a wildlife point of view. Bring this habitat into a garden and you will never be short of interest. Plus, the braai fire will always be burning!