Noogoora Burr © Geoffery Sinclair

​​Noogoora Burr​

​​Xanthium occidentale​

Quick facts

Status
Declared Pest
Life Cycle
Annual
Growth Form
Herb
Origin
Southern North America, Central America
Flowers
Cream/Green/Yellow/Brown
Dispersal
Attached seeds
Toxicity
Seedlings toxic to livestock

Names

Other Common Names: Cockleburr, Clotbur, Large Cockleburr, Rough Cockleburr, Californian Burr, European Cocklebur

Synonyms: Xanthium ​chinense​, Xanthium strumarium, Xanthium pungens.

Form and function

Classified as C2 (Eradication) across most of the state, this species is managed under a C3 (Management) classification in the Shires of Broome, Derby-West Kimberley, Halls Creek and Wyndham-East Kimberley. It is an annual species that germinates after the wet season in northern Australia, while in southern Australia it germinates in early summer in moist soils. Plants typically reach maturity within 2 to 4 months, remain actively growing for around 6 months and senesces after seed set. They can grow to 2 to 2.5 metres in height and produce seeds that may remain viable in the soil for up to six years. Fire may kill plants present at the soil surface, although its effectiveness depends on fire intensity and site conditions.

Flowers

  • Separate male and female flowers occur on the same plant.
  • Male flowers: cream or creamy green (clusters at the end of branches)
  • Female flowers: yellowish green to brown (at the base of leaves and at the ends of the main stem and side branches)
  • Flowers are very small and inconspicuous. 

Noogoora Burr flowers © DBCA

Leaves

  • Large, rough-textured leaves resembling grapevine leaves.
  • Broadly ovate to triangular with 3 to 5 lobes and coarse teeth.
  • Dark green with distinctive purplish veins.
  • Lower leaves are opposite, upper leaves are alternate.

Noogoora Burr leaves © Geoffrey Sinchair

Fruits

  • Fruits called burrs
  • Hard, woody, egg-shaped burrs, 16 to 22 mm long.
  • Covered with hooked spines and two straight terminal beaks.
  • Green when young, turning brown as they mature.
  • Each burr contains two seeds.

Noogoora Burr © Heather Knowles

Habitat

Grows best in deep, fertile soils, particularly in areas influenced by summer rainfall, flooding or irrigation. Commonly found along roadsides, disturbed sites, waste areas, rivers, waterways and lakes, it can extend into semi-arid environments via watercourses. It tolerates intermittent waterlogging, flooding, and moderate to high soil salinity but thrives where competition from other vegetation is limited. In northern Australia, it occurs along rivers and under trees in native pastures, while in southern Australia it is typically associated with well-drained waterways and lakes.

May be confused with...

Similar non-native species: Similar to Bathurst burr (Xanthium spinosum) however, they can be distinguished easily by three long sharp spines on the stem of the Bathurst burr, while stem of Noogoora burr is spineless.

How does it spread?

A single plant can produce thousands of burrs. Each burr is covered in numerous hooked spines, allowing it to easily attach to clothing, livestock, mammals fur and bird feathers. Burrs are also dispersed by water, enabling them to spread along waterways and across floodplains during flooding events.

Noogoora Burr burrs sticking to clothing © DBCA

Why is it a weed?

Significant threat to wetlands, drainage lines and floodplain habitats, where it can form dense thickets that suppress native understorey vegetation and reduce biodiversity. It is also an agricultural weed, competing strongly with pastures and crops, while its burrs contaminate wool and its seedlings can be toxic to livestock.

History

​​They were first found in Noogoora Station on the Brisbane River, Queensland in the 1860s. Initially introduced as cotton seed imported from either the Mississippi Delta region of the United States or from India.​ 

Noogoora burr* is a Declared Pest in Western Australia under section 22(2) of the BAM Act. 

How to control

Arum Lily

Physical

Arum Lily

Chemical

Arum Lily

Biological

Noogoora burr* is a Declared Pest in Western Australia under section 22(2) of the BAM Act. It is assigned C2 Eradication for most of the state and C3 Management in the state's north (Broome, Derby-West Kimberley, Halls Creek, and Wyndham-East Kimberley), and a Prohibited keeping category

This weed MUST BE REPORTED. Notify Pest and Disease Information Service (DPIRD)/

*Listed as the synonym Xanthium strumarium L.

Physical

Manual removal, using equipment such as chippers or hand hoe, is only effective in early stage and small infestations before flowering and burr formation. Slashing or mowing can be used in clean-up operation following chemical treatment but required additional attentions on burrs of the plants to be collected so that they cannot set the seed anymore. Also, periodical monitors should be conducted especially on the flood prone areas as they have higher risk of germination.

Chemical

​​Different herbicides are recommended based on the different time of year/season.

​Actively growing plant (600 g/kg metsulfuron methyl)

​Apply 7.5 g of metsulfuron methyl (600g/kg) in 100L to actively growing plants using a foliar application method, ensuring full leaf coverage. Plants under moisture stress will not be controlled so it is better to obtain rainfall within 4 weeks of application to wet the soils to maximise weed control.

​Prior to burr formation (360g/L, 540g/L and 700g/L glyphosate)

​Use the lower rate for plants up to 15 cm height and use the upper rate for taller weed or dense weed infestation.

​1. 360 g/L Glyphosate present

Apply a mix of 500 to 700 mL of glyphosate (360 g/L) per 100 L of water for handgun application, or 75 to 100 mL of glyphosate (360 g/L) per 15 L of water for knapsack application.

​2. 540 g/L Glyphosate

Apply a mix of 330 to 480 mL of glyphosate per 100 L of water for handgun application, or 50 to 70 mL of glyphosate per 15 L of water for knapsack application. Apply when plants are actively growing and not under stress from drought.

​3. 700 g/L Glyphosate present

Apply a mix of 3 to 5 g of glyphosate per litre of water for handgun or knapsack application. Apply when plants are actively growing and not under stress from drought.

Biological

Noogoora Burr rust fungus © DBCA

A rust fungus (Puccinia xanthii) was accidentally introduced into Brisbane in 1975 and has been shown to attack Noogoora burr, reducing plant growth. The fungus is best suited to Mediterranean climates and is less effective during the hot, low-humidity conditions under which Noogoora burr actively grows in the Kimberley. The rust is being released in bushland areas of southern Western Australia from 2026.

 

Another biological control agent, the moth Epiblema strenuana, is widely established in the Northern Territory, where it damages stems and reduces seed production. Although it is not currently known from the Kimberley, efforts may be made to introduce it to Western Australia if Noogoora burr becomes a significant weed in bushland environments.

Further
reading

Minor use permits
external link Permit PER96598 for metsulfuron methyl
external link Permit PER96570 for glyphosate

Weed Distribution Map

LSID number: [51311048] | full LSID: [https://id.biodiversity.org.au/taxon/apni/51311048] | field_lsid: [] | taxon: [Xanthium occidentale​]

ALA Reference

References

  • Agriculture Protection Board of Western Australia. (1990) Noogoora burr. APB infonote.
  • Centre for Invasive Species Solutions (CISS). (2024). Noogoora Burr, Cockleburr, Clotbur, Large Cockleburr, Rough Cockleburr, Californian Burr, European Cocklebur. Xanthium strumarium L. weeds Australia
  • Department of Energy, Environment and Climate Action. (2026) Noogoora burr. Agriculture Victoria.
  • Department of Environment and Natural Resources. (n.d.). Biological control of Noogoora burr in the Katherine Region. Northern Territory Government.
  • Department of Primary Industries and Regional Development. (2024) Noogoora burr and its control. Government of Western Australia. Factsheet DPIRD-170.
  • Department of Primary Industries & Regional Development. (2023) Noogoora burr (Xanthium occidentale). NSW WeedWise.
  • Edgar, V. & Grace, B. (2004) Experimental inoculations of the rust fungus Puccinia xanthii, a biological control agent against Noogoora burr (Xanthium occidentale) in northern Australia. Plant Protection Quarterly,19(3).
  • Brisbane City Council Weed Identification Tool Noogoora burr Xanthium occidentale
  • Agriculture Victoria Noogoora burr

Life Cycle - South

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Notes
Germination
Active growth
Flowering
Seeding
Regularly or most commonly
Occasionally, given suitable conditions

Life Cycle - North

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Notes
Germination
Active Growth
Flowering
Seeding

Management

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Notes
Physical
Chemical
Optimal
Potentially, but conditionally dependent
Last updated: October 2026