VACHELLIA KARROO II

Among the indigenous trees in bloom at the moment is the Vachellia karroo (I will always think of it as Acacia karroo!), commonly called Sweet thorn, which grows almost everywhere in South Africa as well as in the rest of Africa. It is interesting to note that the common name is derived from the edible gum which is exuded from wounds in the bark, rather than from the fragrance of the flowers.

Its growth varies in size and habit depending on the climate. Those growing around where I live in the Eastern Cape tend to be fairly small and compact, while some of the ones growing along dry water courses in the Mountain Zebra National Park are tall trees. I have noticed several Vachellia karroo trees in this park hosting a type of hemi-parasite known as Agelanthus sp. on their branches.

The trees are fast growing and drought-resistant, with branching usually occurring close to the ground. They have a distinctive round crown and are covered with tiny golden yellow puff-ball / pompon type flower heads during the summer, which are delightfully sweet-scented.

The bark can be rough and fissured, while the long, straight white thorns formed in pairs are characteristic of these trees. Funnily enough, it is these thorns that I miss whenever I have been out of the country for a while.

Pods produced after flowering are initially green, but turn a rusty to dark brown colour when mature.  They vary in shape from almost straight to sickle-shaped. Animals eat the leaves, pods and flowers. The latter produce large quantities of nectar and pollen which attracts a variety of insects. The presence of these trees in the veld is an indicator of sweet veld – prized for good grazing and fertile soils.

Birds build their nests in these trees too. This rather untidy one belongs to a White-browed Sparrow-weaver.

 

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