Cumbungi

• Water weed with leaves 1m long.
• Leaves grow in bunches from below water level, are flat or slightly rounded, sometimes springy.
• Flowering stems grow erect from middle of leaf cluster.
• Stems are round, stiff, with 2 brown, oblong, compact masses of small, furry flowers near top.
• Flower masses are sometimes separated by short stem.
• On maturity, upper mass disperses, leaving 10-20cm dark brown, velvety spike.

• Grows in fresh or brackish, slow-moving or stationary water up to 2m deep.

• Grows in fresh or brackish, slow-moving or stationary water up to 2m deep.

Economic

• Invades slow-moving waterways, dams, channels and drains.
• Reduces water quality.
• Reduces stock access to water.

Social

• Provides breeding places for vermin and mosquitoes.

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

Mechanical control

• Slashing while seed head is still green gives some control.
• Repeated slashing is necessary to maintain control.

Herbicide control

• Spray herbicides when plant is actively growing and before seed sets.
• Safest control method, and only alternative where water is for household or recreational use, is to spray with glyphosate using either low-volume or high-volume methods.
• As long as care is taken to avoid spraying non-target plants, these methods are safe in any situation. There is no need to withhold stock or change methods of water usage. Treatment should be repeated annually to ensure that cumbungi does not reinfest to any great degree. To minimise water-quality problems caused by dead plants collapsing into water, burn plant above water surface 6 weeks after spraying.
• In waterways, channels and drains where water is not used for household, gardening or recreational purposes, 2,2-DPA (a soluble powder) can be used. This product, however, is not always readily available.
• Amitrole-T is also effective and economical for spot spraying in irrigation channels, and can be used when channels are full.
• In bore drains and dams where water is not used for household, gardening, or recreational purposes, glyphosate/Roundup or Diurex WG can be used.
• Glyphosate or Roundup can be used in pasture situations; however, care must be taken as these herbicides will kill pasture grasses and legumes.

See the Cumbungi fact sheet (PDF, 2.3MB) for herbicide control and application rates.

Biological control

• No known biological control agents.

• Cumbungi 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 and animals in their area. This plan may include actions to be taken on Cumbungi. Some of these actions may be required under local laws. Contact your local government for more information.