Noogoora burr

• Upright shrub to 1m tall, occasionally to 2.5m, short-lived, usually an annual.
• Stems are purple, green-blotched, covered with stiff hairs.
• Leaves are 15cm in diameter, dark green on upper surface, roughly textured with minute bristles.
• Upper leaves are alternate, lower leaves are arranged opposite.
• Flowers are greenish-yellow and inconspicuous, with separate male and female flowers appearing in leaf axils toward end of branches.
• Fruits are hard, woody, spiny burrs, 1.2cm to 2cm long, with hooked spines containing 2 seeds.
• Seeds are grey or black, 4-15mm long, 5-7mm wide, flattened on 1 side, with 1 seed in each pair usually slightly larger than the other.

• Found along river and creek flats, on roadsides, and in pasture land.

• Widespread in Queensland, occurring in tropical, central and west regions.

• Seeds germinate in late winter to summer.
• Flowering occurs January-March.

Economic

• Contaminates wool, reducing value by increasing processing costs.
• Denies sheep access to watering points.
• Competes with pasture and summer crops.
• Seedlings are poisonous to domestic stock if eaten in sufficient quantities.

• Spread by seed in burrs.
• Burrs are spread by attaching to animals, clothing and bags.
• Burrs can also float on water.

• Find out how farmers can prevent weed spread.
• Find out how gardeners and outdoor enthusiasts can prevent weed spread.

Physical control

• Reduce infestations by preventing seeding.
• Cultivation or hand-pulling is effective for isolated plants.

Herbicide control

• Spraying with 2,4-D or MCPA before flowering will give favourable results. As plants mature, higher rates are necessary.

See the Noogoora burr fact sheet (PDF, 2.1MB) for herbicide control and application rates.

Biological control

• Rust fungus (Puccinia xanthii) provides a high level of biological control across most of Australia, except in arid and Wet Tropics regions.
• Rust affects leaves and some stems and overwinters in dead plant material as spores.
• Stem-galling moth Epiblema strenuana, introduced for parthenium control, also contributes to control of Noogoora burr in some areas.

• Noogoora burr is not a prohibited or restricted invasive plant under the Biosecurity Act 2014. However, by law, everyone has a general biosecurity obligation (GBO) to take reasonable and practical steps to minimise the risks associated with invasive plants under their control.
• Local governments must have a biosecurity plan that covers invasive plants in their area. This plan may include actions to be taken on Noogoora burr. Some of these actions may be required under local laws. Contact your local government for more information.