Karroo thorn is a shrub or tree with distinctive long white thorns and ball-shaped fluffy yellow flowers. It forms dense thickets that compete with other plants and restrict movement of people and animals.
Karroo thorn grows quickly and forms dense thorny thickets. It:
Karroo thorn usually grow to a height of 12 m tall. It is usually evergreen, but can lose its leaves in very dry or cold conditions.
The leaflets are:
Karroo thorn looks similar to mimosa bush (Vachellia farnesiana), prickly acacia (Vachellia nilotica), giraffe thorn (Vachellia erioloba), umbrella thorn (Vachellia tortilis) and other non-indigenous acacias.
Compared to karroo thorn:
Call the NSW DPI Helpline if you see anything that you suspect might be karroo thorn, prickly acacia or any non-Indigenous acacia other than mimosa bush.
There are no current known infestations of karroo thorn in NSW. However, its preferred habitat and climate are similar to the native grasslands of central NSW so it could invade NSW rangelands. It also has potential to invade riparian areas in many parts of NSW.
Karroo thorn grows in Africa, Asia, South America and parts of Europe.
It is a favourite food of the black rhinoceros and was planted in Australian botanical gardens and zoos to represent African landscapes. All karroo thorn plants that were growing in NSW have been eradicated.
Karroo thorn grows in many different soils types, climates and at many altitudes. Growth is limited by intense cold or lack of moisture.
It grows best in areas with:
Karoo thorn plants start producing fruit within 2 years. Large trees can produce up to 19,000 seeds per year. Seeds can remain viable in the soil for at least 7 years. Germination is improved by fire, weathering and passing through an animal’s gut.
The seeds can spread long distances in the droppings of animals, especially livestock that eat the pods. Seeds and pods can also be spread through waterways and short distances by wind.
CRC for Australian Weed Management (2003). Weed management guide - Karroo thorn.
Queensland Department of Agriculture and Fisheries (2020). Identification of prickle bushes Prickly acacia (Vachellia nilotica), Mesquite (Prosopis spp.), Parkinsonia (Parkinsonia aculeata), Mimosa bush (Vachellia farnesiana). Retrieved 25 August 2020 from: https://www.daf.qld.gov.au/plants/weeds-pest-animals-ants/weeds/a-z-listing-of-weeds/photo-guide-to-weeds/mimosa-bush?a=72195
Queensland, Department of Employment, Economic Development and Innovation. (2011). Weed risk assessment – Karroo thorn
Please do not attempt to treat or dispose of this weed yourself. Report this plant if you see it anywhere in NSW by calling the helpline listed at the top of this page immediately.
NSW DPI will lead an initial response for the treatment and disposal of the plant to stop it from spreading.
Since karroo thorn is not established in NSW, finding new infestations early gives us the best chance of eradicating it.
Basal bark, cut stump or stem injection methods can be used to apply herbicides. The plant reshoots from the base if cut, therefore herbicide should be applied to the stump after cutting and treated plants should be checked.
See Using herbicides for more information.
PERMIT 9907 Expires 31/03/2025
Fluroxypyr 200 g/L
(Starane™)
Rate: 35mL per L diesel/kerosene
Comments: Basal bark
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Fluroxypyr 333 g/L
(Starane™ Advanced)
Rate: 21 mL per L diesel/kerosene
Comments: Basal bark
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Various products)
Rate: One part product to 1.5 parts water
Comments: Cut stump, drill, frill axe or injection
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
with Metsulfuron-methyl 600 g/kg (Various products)
Rate: 1:1.5 glyphosate to water + 1 g metsulfuron to 1 L water
Comments: Stem injection
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.
Area | Duty |
---|---|
All of NSW | General Biosecurity Duty All plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable. |
All of NSW |
Prohibited Matter
A person who deals with prohibited matter or a carrier of prohibited matter is guilty of an offence. A person who becomes aware of or suspects the presence of prohibited matter must immediately notify the Department of Primary Industries |
Reviewed 2020