Noogoora burr (Xanthium occidentale)

Noogoora burr is an annual plant that produces a woody burr. It is widespread through most of NSW. It is very similar to other Xanthium burr species.


How does this weed affect you?

Noogoora burr competes with summer crops and pastures. In crops such as cotton, corn and soybeans, these weeds can out-compete crops for moisture and nutrients. Left untreated, infestations result in reduced yields and downgrading of grain due to contamination. These weeds also cause problems in livestock production where price penalties can apply for contaminated wool. Large plants can create barriers for livestock and people around watercourses and in irrigation areas. The burrs can cling to livestock, making handling difficult and causing physical injury to people and the livestock.

Where is it found?

Noogoora burr is native to the southern United States of America, Mexico and West Indies. In New South Wales Noogoora burr is widespread, found in most areas, except for the southern tablelands.

How does it spread?

Noogoora burr is an annual plant that reproduces by seed contained in a burr. The burrs are usually dispersed from the plant in autumn and winter but they may remain attached on undisturbed plants until the following spring.  The burrs are spread by:

  • sticking to wool and fur of animals
  • floating in waterways
  • movement of contaminated grain
  • movement of contaminated gravel
  • machinery.

Seeds germinate when the soil is moist in late winter to summer. Flushes of germination can occur after summer storms or irrigation events. On flood prone areas large germination events are common after floods.

What does it look like?

Noogoora burr is a stout, erect, single stem or many branched annual plant with large leaves similar to those on grapes. Mainly growing in summer, they can grow up to 2 m high. Noogoora burr, California burr, Italian cockleburr and South American share this description. However, there is extensive variation between these species, especially in the number and length of the burrs and the spines on the burrs.


Noogoora burr plants tend to be single stemmed when growing in dense patches. Isolated plants have branched and spreading stems. Stems are purple/green mottling and hairy.


Noogoora burr has grapevine-like leaves that grow alternately on the stems. The upper surface is darker green with purplish veins. Their shape is broad ovate to triangular, cut in 3-5 lobes. They are rough textured.

Fruit (burrs)

The main way of distinguishing between Xanthium burr species is by the burr shape and size. The fruit or burr of the Noogoora burr is hard and woody, 16-22 mm long, more or less egg-shaped. It is densely covered with hooked spines 1-3 cm long and ending in longer terminal spines (or beaks) 3-5 mm long that are straight, almost parallel. The burr turns brown when mature.

What type of environment does it grow in?

Plants are commonly found in riparian areas, along roadsides, in wasteland and in pastures or cultivated areas that are low lying or subject to periodic flooding. They are capable of forming extensive dominant stands in wet summers.

These species grow in a variety of climates. They grow best in deep fertile soils but are found on a variety of soil types.


Contributing authors: Annie Johnson, Bob Trounce.

Technical reviewers: Graham Charles, Stephen Johnson and Bruce Auld.


Cotton CRC (2002) WEEDpak a guide for integrated management of weeds in cotton. Eds Stephen Johnson, Graham Charles, Ian Taylor and Grant Roberts. Cotton CRC, Narrabri.

Hocking PJ. and Liddle MJ 1995, Xanthium occidentale Bertol. complex and X. spinosum L. In Groves RH, Shepherd RC H and Richardson RG (eds), Biology of Australian Weeds, vol 1. RG and FJ Richardson Publishers. Melbourne, pp. 241-289.

National Herbarium of NSW. PlantNET – FloraOnline. Accessed 27 March 2008.

Parsons, WT and Cuthbertson, E G (1992) Noxious Weeds of Australia, 2nd ed. CSIRO publishing.

More information

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Prevention of seed set is the most important part of managing Noogoora burr plants and eliminating infestations. Trials have shown that six years prevention of seed set leads to a decline in populations to 1% of previous populations. Repeated control is often needed as many germination events can occur from late winter to summer. Early control can prevent competition with crops and pastures, and later control can prevent seed set of plants that may have been missed by earlier control efforts. Large populations can be treated with herbicides, cultivation or slashing; follow-up control of smaller populations may include spot spraying, chipping (or hand-hoeing) or inter-row cultivation in crops.


Cultivation is an effective method of controlling the seedlings of these weeds. Successive flushes of seedlings during the summer may require follow up control. Inter-row cultivation is commonly used in row cropping such as sorghum, corn and cotton to control seedlings that have germinated after irrigation events.


Slashing or mowing are useful in clean-up operations after spraying with herbicide or if infestations are small and scattered. Any burrs from the plant should be removed from the equipment to prevent spread.


Chipping or hand hoeing is only economical for small areas, individual plants or isolated populations. It is an effective follow up control method for plants not controlled by other methods to prevent seed set.


After controlling burr plants it is important to monitor these sites for further germination events. High risk areas for new infestations include flood prone areas or areas where stock from burr infested areas have been.

Pasture management

Maintaining ground cover in pastures is vital. Pasture gaps result in an increase in burr germination and seedling survival. It is important to ensure that pastures are not overgrazed in spring and summer to reduce the potential for the establishment of burrs and other weeds.


Adult plants are not easily eaten by livestock, due to the roughness of the leaves and stems. Care needs to be taken when grazing to ensure there are no seedling plants, which are toxic to animals and could result in death.

Biological control

Four species of insects and one rust fungus have been released in Australia for the biological control of Noogoora burr. With the exception of the rust fungus (Puccinia xanthii) which has had a significant impact in areas of higher rainfall, these agents have had little or no effect in NSW, mainly due to their inability to tolerate the uncertain climatic conditions where Noogoora burr is found.


These plants are susceptible to a range of foliar and residual herbicides.

Foliar herbicides are most effective if the plants are young and actively growing. Plants suffering from moisture stress are difficult to kill. Older plants may require repeat applications. Late control with some herbicides, when the burrs are green, can result in seed sterility – however this is not recommended as the primary form of control.

In crops, residual pre-emergent herbicides are useful, although there are sometimes problems as the burr can germinate and emerge from relatively deep in the soil, below the residual herbicide band. Follow-up control in the form of chipping or inter-row cultivation may be required. Spot spraying is an important tool for areas that are difficult to access and for scattered plants.

Herbicide options

Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website

See Using herbicides for more information.

2,4-D 300 g/L + Picloram 75 g/L (Tordon® 75-D)
Rate: 1.0 L/ha
Comments: Boom spray application
Withholding period: 1-8 weeks (see label).
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

2,4-D amine 625 g/L (Amicide® 625)
Rate: 800 mL–1.1 L/ha
Comments: Seedlings only.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

2,4-D LV ester 680g/L (Estercide® Xtra)
Rate: 1.7 to 3.3 L per hectare
Comments: Boom spray application from seedlings to preflowering
Withholding period: 7 days
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

Fluroxypyr 200 g/L (Starane™)
Rate: 75 mL per 100 L of water
Comments: Apply to actively growing plants. Seedlings and young plants to 40 cm high.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

Fluroxypyr 333 g/L (Starane™ Advanced)
Rate: 45 mL in 100 L of water
Comments: Apply to actively growing plants. Seedlings and young plants to 40 cm high.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

MCPA 500 g/L (Various products)
Rate: 1.0–2.0 L/ha
Comments: Spray young seedlings only.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

Metsulfuron-methyl 300 g/kg + Aminopyralid 375 g/kg (Stinger™)
Rate: 14 g per 100 L of water
Comments: Hand gun application.
Withholding period: 3 - 56 days (see label)
Herbicide group: B, Inhibitors of acetolactate synthase (ALS inhibitors) + I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: High/Moderate

Metsulfuron-methyl 600 g/kg (Various products)
Rate: 7.5 g per 100 L of water
Comments: Apply to actively growing plants. Do not apply to plants under stress.
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: B, Inhibitors of acetolactate synthase (ALS inhibitors)
Resistance risk: High

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Biosecurity duty

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.

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For technical advice and assistance with identification please contact your local council weeds officer.
For further information call the NSW DPI Biosecurity Helpline on 1800 680 244 or send an email to

Reviewed 2014