It is integrally part of our country's history having been used for everything from raft-making to sewing needles and fencing for the houses of the royal Zulu women. The thorns were even used by early naturalists to pin the insects they collected!

Vachellia karroo may be found from the Western Cape through to Zambia and Angola. In tropical Africa it is replaced by Acacia seyal, which has probably also been renamed.

It is found in a variety of habitats from low lying areas to highveld, although not usually found in mist belt and montane areas. It is an indicator of sweet veld which is prized for the good grazing and fertile soils. If an area is overgrazed the sweet thorn becomes invasive.

Vachellia karroo has a life span of 30-40 years and is an adaptable pioneer, able to establishing itself without shade, shelter or protection from grass fires. Once over a year old, seedlings can resprout after fire.

This tree has a long taproot which enables it to use water and nutrients from deep underground, this and its ability to fix nitrogen, lead to grasses and other plants thriving in its shade.

Water well and deeply (shallow, frequent sprinklings only encourage shallow root growth) until established. Plant with plenty of compost, bonemeal or superphosphates (commercial tree tablets also work well). The growth rate is fast, up to 1m per year.

The leaves are finely textured and dark green.

The thorns are paired, greyish to white and are long and straight. On mature trees, the thorns may be quite short. They may be held at 90° to the stem or raked forward slightly. Technically the thorns are called "spines" and are developed from modified stipules (small, leaf-like scales, seen at the base of the leaf-stalk).

The flowers appear in early summer in a mass of yellow pompons. Many insects visit and pollinate these flowers.

The flowers are sweetly scented and are renowned for attracting insects which are essential to any bird garden.