Spiny burrgrass - spinifex (Cenchrus spinifex)

Spiny burrgrass is a summer-growing grass. It can spread rapidly to develop large infestations.

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How does this weed affect you?

Spiny burrgrass (spinifex) can form dense infestations in pastures, orchards, native vegetation and along roadsides. The sharp burrs can:

• injure livestock, native animals and pets
• injure people especially shearers, abattoir workers and horticultural staff
• reduce wool and hide values
• make shearing or working in orchards or crops difficult and more expensive
• contaminate agricultural produce including hay and dried fruit
• compete with native plants.

What does it look like?

Spiny burrgrass (spinifex) is an annual or occasionally perennial tufted grass up to 80 cm high.

Leaves are:

• up to 20 cm long and 2–6 mm wide
• rough to touch or sparsely hairy
• flat or folded.

Seedheads are:

• up to 8.5 cm long consisting of up to 40 burrs (usually much less)
• often partly enclosed in a leaf sheath
• present in summer to autumn.

Burrs:

• are straw coloured
• have 11–43 spines, each up to 5 mm long
• have small bristles
• are stalkless.

Seeds are:

• 3–4 mm long and 2 mm wide
• oval shaped. 

Stems are:

• either upright or spreading
• branched from the base
• hairless
• flattened, particularly at the base.

Roots are:

• fibrous
• usually shallow but may be over 30 cm deep.

Similar looking plants

Spiny burrgrass (spinifex) looks similar to other Cenchrus species weeds:

• Spiny burrgrass - longispinus (Cenchrus longispinus) has longer spines, up to 7 mm long and they are on stalks. There are 40–70 spines per burr and they are often tinged purple.
• Mossman River grass (Cenchrus echinatus) only has one row of spines. The spines are shorter and may be tinged purple. 

Where is it found?

In NSW, most infestations are in the Murray, Riverina, and Central West regions. Plants have also been recorded in the Greater Sydney, Hunter, Central Tablelands, Western and North West regions.

It is native to Northern and Central America

What type of environment does it grow in?

Spiny burrgrass (spinifex) grows best in temperate and semi-arid regions. It tolerates some frost and low temperatures. Most plants are found in areas with 250-500 mm annual rainfall.  It usually grows on sandy to light soils. Spiny burrgrass (spinifex) grows in:

• pastures
• crops
• native rangelands, grasslands and open woodlands.
• coastal environments
• disturbed sites such as roadsides
• creeks and riverbanks. 

Maps and records

• Recorded presence of Spiny burrgrass - spinifex during property inspections (Map: Biosecurity Information System - Weeds, 2017-2026)
  These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Records reflect the presence of the weed on the date of inspection.
  
  

How does it spread?

By seeds

Each plant can produce up to 1000 seeds.  Seeds are usually produced from late spring to late autumn depending on available soil moisture. In warm dry weather plants can produce seeds four weeks after germinating. Seeds can remain dormant in the soil for up to 3 years and can sprout from as deep as 25 cm below the spil surface.

Seeds are spread:

• in flowing water (including in irrigation channels)
• by the burrs attaching to clothing and boots
• via wool and fur of livestock and native animals
• by roadgraders, slashers and vehicle tyres
• in contaminated sand or soil.

References

Identic & Lucid (2016). Weeds of Australia Fact sheet: Cenchrus longispinus (Hack.) Fern. Retrieved 22 May 2026 from: https://keyserver.lucidcentral.org/weeds/data/media/Html/cenchrus_spinifex.htm

Johnston, W.H. (1989). ‘Consol lovegrass (Eragrostis curvula complex) controls spiny burrgrass (Cenchrus spp.) in south-western NSW,’ Australian Journal of Experimental Agriculture, 29, 37–42.

Parsons, W.T. and Cuthbertson, E.G. (2001). Noxious Weeds of Australia, second edition, CSIRO Publishing, Collingwood, Vic.

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 22 May 2026 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Cenchrus~spinifex

Twentyman, J.D. (1974). ‘Control of vegetative and reproductive growth in sand burr (Cenchrus longispinus),’ Australian Journal of Experimental Agriculture and Animal Husbandry, 14, 764–770.

More information

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Control

Successful spiny burrgrass control relies on follow-up after the initial efforts and preventing plants from seeding. This means regularly looking for and killing new seedlings for 3 to 5 years. Using a combination of control methods is usually more successful.

Prevention

Prevent spiny burrgrass from spreading from infested areas by:

• excluding livestock from areas with burrs if possible
• restricting vehicle and machinery access
• cleaning vehicles or machinery before leaving an infested site.

Physical control

Hand pull or dig out plants if the infestation is small. If burrs are present, wear gloves and other protective clothing and dispose of plants appropriately.

Pasture management

Spiny burrgrass does not compete well with vigorous, perennial pastures. Good ground cover in spring and summer will limit spiny burr grass germination and seedling establishment. Maintaining ground cover and perennial grasses, by managing grazing and using fertiliser in existing and native naturalised pastures can help to limit infestations.

Establishing perennial pastures is expensive so thorough preparation and research into suitable species and varieties is required. The establishment of adequate plant numbers is the first step to a successful pasture. Seek advice from your agronomist on the best pasture establishment steps for your situation.

Competitive summer grasses  have proven successful in controlling spiny burrgrass on sandy soils. These grasses are summer-growing perennials and are excellent competitors where the weed is a problem. They establish readily, are drought-tolerant and are reasonably palatable to stock (depending on grazing management). Contact your local agronomist for grasses suitable for your area. 

Grazing

Livestock eat spiny burrgrass. In paddocks dominated by spiny burrgrass, heavy grazing may suppress growth and burr production in the short term. Livestock could also spread infestations so it is important to remove stock before seeding commences. Avoid overgrazing that exposes bare soil as this will allow the spiny burrgrass seeds to sprout. 

This method is not suitable if spiny burrgrass is sparsely scattered throughout a paddock.

Cultivation

Cultivation followed by cropping and herbicides can be used to manage spiny burrgrass consult with an agronomist for recommendations that are suitable for the location.

Herbicide control

Spray actively growing plants. Ensure all of the foliage is covered. Herbicide rates may vary for different sized plants, check the labels for appropriate rates.

Herbicide options

See Using herbicides for more information.

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Glyphosate 360 g/L (Various products)
Rate: 500–700 mL in 100 L of water
Comments: Spray with a handgun on actively growing. Use the lower rate on weeds up to 15 cm tall and the higher rate for weeds over 15 cm tall.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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Glyphosate 360 g/L (Various products)
Rate: 2.0–3.0 L/ha.
Comments: Boom spray actively growing plants. Use the lower rate on weeds up to 15 cm tall and use the higher rate for weeds over 15 cm tall.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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Glyphosate 360 g/L (Various products)
Rate: 75-150 mL per 15 L of water.
Comments: Knapsack spray. Use the lower rate on weeds up to 15 cm tall and the higher rate for weeds over 15 cm tall.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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Biosecurity duty

The content provided here is for information purposes only and is taken from the NSW 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 pest 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.
Central Tablelands Contain recorded populations across the Central Tablelands region. Goal will be to contain spiny burr grass spread across the whole region with focus on spread or potential spread into production areas.	Regional Recommended Measure * (for Regional Priority - Containment) Whole of region: Land managers should mitigate the risk of the plant being introduced to their land. Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
Western	Regional Recommended Measure * (for Regional Priority - Asset Protection) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should mitigate spread of the plant from their land A person should not buy, sell, move, carry, or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
	*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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Reviewed 2025