Aleman grass
Aleman grass plant and seed head
© Queensland Government
Aleman grass plant
© Queensland Government
Aleman grass stem
© Queensland Government
Native to North and South America, Aleman grass is an aquatic or semi-aquatic perennial grass with smooth, flat leaves. It was introduced to Queensland as a ponded pasture grass.
Aleman grass has now invaded swamps, lake shores, rivers, and seasonally flooded areas, due to its ability to grow in deep water and reproduce vegetatively. Aleman grass has been found in Queensland, Western Australia and the Northern Territory.
Aleman grass is not a prohibited or restricted invasive plant under the Biosecurity Act 2014.
Scientific name
Echinochloa polystachya
Other names
- German grass, creeping river grass
Description
- Aquatic or semi-aquatic perennial grass 1–2.5m tall.
- Leaves are 20–60cm long, 1–1.5cm wide, flat and smooth on surface, rough on edges, tapering towards apex.
- Flower heads are 15–25cm long.
Habitat
- Forms extensive patches in seasonal swamps along streambanks and other seasonally flooded areas.
- Can grow in water that is more than 2m deep.
Distribution
- Naturalised in small areas of Northern and Central Queensland.
Life cycle
- Major growth happens in summer.
- Seed heads appear throughout year.
Affected animals
- Crayfish
- Freshwater production animals
- Birds
Impacts
Environmental
- Forms pure stands in native range, suggesting it out-competes other plants.
- Has potential to invade large areas of wetlands and areas with high average rainfall in Northern Australia.
Economic
- Known weed of rice crops and crayfish production overseas.
How it is spread
- Stems and roots are spread by floodwaters.
- Also spread by vehicles and animals.
Prevention
Control
Physical control
- Dig out small areas of young plants with mattock or similar tool when site is not waterlogged.
Mechanical control
- Treat mature plants and larger infestations with appropriate herbicide.
Herbicide control
- Treat mature plants and larger infestations with appropriate herbicide.
See the Aleman grass fact sheet (PDF, 916KB) for herbicide control and application rates.
Legal requirements
- Aleman grass 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 councils must have a biosecurity plan that covers invasive plants in their area. This plan may include actions to be taken on Aleman grass. Some of these actions may be required under local laws. Contact your local council for more information.