Noogoora burr

Native to America, Noogoora burr is an erect, annual herb with blotched purple stems.

Widespread in Queensland, Noogoora burr is often abundant after spring or summer floods. Its burrs can tangle in sheep fleece, injuring livestock and increasing wool processing costs. Noogoora burr can also impede stock access to watering points, and compete with crops.

Noogoora burr is not a prohibited or restricted invasive plant under the Biosecurity Act 2014.

Scientific name

Xanthium occidentale, syn. X. pungens, X. strumarium

Description

  • 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.

Habitat

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

Distribution in Queensland

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

Life cycle

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

Affected animals

  • Sheep; livestock

Impacts

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.

How it is spread

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

Control

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, 191KB) 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.

Legal requirements

  • 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 and animals under their control.
  • Local governments must have a biosecurity plan that covers invasive plants and animals in their area. This plan may include actions to be taken on certain species. Some of these actions may be required under local laws. Contact your local government for more information.
Last updated
01 July 2016

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