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A picture of a Sweet Thorn

Sweet Thorn

Vachellia karroo

Also known as

Cape Thorn Tree, Umbrella Thorn, White Thorn, Mimosa Thorn, Cockspur Thorn, Acacia, Common Acacia, Karoo Thorn, Cape Gum, Karoodoring, Doringboom, Soetdoring, Witdoring (Afr.), umuNga, Mookana (North Sotho), umuNga (Zulu/Xhosa), Mooka (Tswana), Karru wattle

Photo by girl_meets_garden (All rights reserved)

Full Sun
Easy care
Light watering
Frost Hardy


USDA zone


Minimum temperature

Expected size









  • spring
  • summer
  • autumn
  • winter

This plant has a mild fragrance

More images of Sweet Thorn

A photo of Sweet Thorn
A photo of Sweet Thorn
A photo of Sweet Thorn
A photo of Sweet Thorn
A photo of Sweet Thorn

Sweet Thorn Overview

Vachellia karroo is commonly known by the name Sweet Thorn. Sweet thorns are highly ornamental plants that can be grown as a multi-stemmed shrub or pruned to a single-stemmed tree. Acacia karroo has a rounded crown, branching fairly low down on the trunk and can reach a maximum height of 12 m where water is plentiful. The bark is red on young branches, darkening and becoming rough with age. The dark green leaves are finely textured. Yellow pompom flowers appear in early summer and are pollinated by insects. The crescent-shaped seed pods are flat and sometimes with constrictions between the seeds. They are green when young becoming brown and dry. The pods split open allowing the seeds to fall to the ground. The paired thorns are greyish to white, long and straight. On mature trees, the thorns may be quite short. A beautiful and useful tree that occurs from the Western Cape (RSA) to Zambia and Angola. Is usually linked to the sweetveld (good grazing and fertile soils). The tree is also used in woodworking, firewood, animal feed and nectar for honey making. The tree can live up to 40 years, is a very adaptable pioneer and re-sprouter (grows up to 1m per year). In cool dry areas it becomes deciduous. It has the ability to fix nitrogen in the soil, making it more fertile for grasses. Uses: Gum (sap) is eaten, used in pharmacaceutical products, for confectionary and as an adhesive, wood for woodworking, colourful garden plant (in spring), attracts insects and birds, for shade and wind breaks and has traditional medicinal uses. A strong rope can be made from the inner bark which is pliable enough for rope-making when wet. The flowers produce lots of nectar and pollen for bee-farming and the honey has a pleasant flavour. In arid areas the sweet thorn is an indicator of water, both underground and surface. ZA Distribution: Eastern Cape, Mpumalanga.

How to harvest Sweet Thorn

Can harvest the gum (sap) for eating purposes.

How to propagate Sweet Thorn



Sow in spring; Germination time: 3-12 days; Sow seeds 2-5 mm deep in sandy soil mix.

Special features of Sweet Thorn

Attractive flowers

Attracts butterflies

Wind break


Hedge plant

Can be grown into large hedges.

Drought resistant

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.

Attracts useful insects

Caterpillars of 10 species of butterflies are dependant on the tree for survival. These include, the club-tailed charaxes (Charaxes zoolina zoolina) and the topaz-spotted blue (Azanus jesous).

Attracts birds

Birds also like to make nests in thorn trees as the thorns offer them some protection from predators.

Other uses of Sweet Thorn

Bonsai. Edible gum. Used for chemical products, forage, domestic uses, environmental management, medicinal purposes, fibre, food, drink, and wood.

Animal feed

It is a particularly good fodder tree, stock and game feed on the leaves, flowers and pods.


The gum is edible.


Medicinal uses are wound poultices to eye treatments and cold remedies


The gum can be used as an adhesive and the wood for woodworking.


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