Weed Identification

Australia > > Karoo Thorn

Karoo Thorn

Acacia karroo

IMPORTANT: IF YOU SUSPECT THE PRESENCE OF THIS PLANT, PLEASE REPORT IT BY CALLING 1800 084 881 (local call cost anywhere in Australia).

Family: Fabaceae or Mimosaceae.

Form: Tree

Origin: Native of Africa.

Flowers/Seedhead: Produced in spring and summer.

Description: Small tree to 15 m high. Bark rough, red-brown to black.Young branches and branchlets red when outer bark peels off. Seedpod thinly woody, sickle-shaped, to 16 cm long and to 1 cm wide, hairless and slightly constricted between seeds, opening at maturity.

Distinguishing features: Distinguished by paired white straight spines (modified stipules) usually to 7 (rarely to 17) cm long, white, dark-tipped; mature leaves bipinnate to 120 mm long and to 50 mm wide, green, primary divisions (pinnae) in 27 pairs, leaflets 47 mm long, 13 mm wide in 820 pairs; flowerheads 1015 mm wide, 46 per leaf axil, golden yellow, globular.

Dispersal: Spread by seed.

Thorny plant South Africa Jan
Photo J. R. Hosking.

Inset: Dubbo Zoo March.
Photos P. Gray.

Notes: Considered to be useful in South Africa. One of the most widespread trees in Africa. Potentially a major woody weed in Australia. Introduced a number of times and planted at scattered locations in southern Australia as a typically African tree.


    Trees of southern Africa. K. Palgrave, 1995, pages 241242.

White spines, bipinnate leaves & round,
golden-yellow flowerheads.
Photo J. R. Hosking.

Paired, white spines & sickle-shaped
Photos M. Arundell.

This weed has been included in the WEEDeck field guide as card T19

More information about WEEDeck is available from Sainty & Associates Pty. Ltd.


Australia > > Karoo Thorn


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