Common name: Bur cactus
Category: 1a NEMBA
Opuntia salmiana J.Parm. ex Pfeiff. is a low shrub 0.3–1 m high, much branched; branch segments terete, up to 25×1 cm, not tuberculate, often tinged red. Spines absent or 3–5, bristle-like, up to 1.5 cm long, barbed. Leaves very small, 1–2 mm long, tinged purple, caducous. Flowers white or pale yellow. Fruit oblong-ellipsoid, about 1 cm wide, bright red.
Bur cactus is native to the Gran Chaco region in South America, from Bolivia, Paraguay and Argentina. In many areas in its native range the species is locally abundant, particularly in the transition between humid and dry Chaco regions.
How it spreads
Bur cactus spreads mainly by vegetative means. There is no evidence that the seeds are viable. It resembles the jointed cactus (Opuntia aurantiaca), but is less spiny with long round cladodes that do not detach that easily. Bur cactus have fruits that proliferate joints which develop into new plants. These joints are clonal propagules also known as bulbils and are easily detached by passing animals. They are armed with many small bristle-like barbed spines which attach easily to fur, clothes or skin for potential long distance dispersal. It also produces attractive red fleshy fruits that increases the chances of the bulbils being spread by frugivores.
History in South Africa
Bur cactus is currently known from only one locality, north of Brits, in the North-West Province. At this locality, bur cactus occurs in dense stands in savannah and grasslands habitats. It is mostly abundant under canopy or shady areas.
Bur cactus creates dense infestations that can dominate native vegetation and form impenetrable thickets for wildlife and the small bristle-spiny cladodes can adhere to any animal brushing past, spreading the cactus vegetatively over considerable distances.
How to eradicate
There are no registered herbicides in South Africa for this species.
What can you do to help? Report sightings of these plants to the Invasive Species Programme at SANBI. We will need to know its locality (the exact locality, supply any landmarks of GPS information if possible).
Email address: firstname.lastname@example.org
Tel: 021 799 8403
- Oakley, L. and Pin, A. 2013. Opuntia salmiana. The IUCN Red List of Threatened Species. Version 2014.3. www.iucnredlist.org
- Walters, M., Figueiredo, E, Crouch, N.R., Winter, P.J.D., Smith, G.F., Zimmermann H.G. and Mashope, B.K. 2011. Naturalised and invasive succulents of southern Africa. ABC Taxa 11: 193-195
See more on invasive alien plants and their categories
Compiled by Thulisile Jaca - December 2014