Indian bluegrass (Bothriochloa pertusa) originated in India and is now naturalised on a wide range of soils in Queensland. It grows in a low, creeping manner and spreads by seed and runners. Indian bluegrass spreads readily into bare areas. It is closely related to our native mitchell (Bothriochloa ewartiana) and has similar looking seed heads. The creeping habit provides good cover for preventing soil erosion and it is valuable for lawns and recreational areas.

On this page:

• History
• Plant characteristics
• Local observations
• Summary

History

Indian bluegrass is widely distributed from east Africa to Asia and naturalised in tropical America. It was introduced by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) at Gatton College and an area near Rockhampton in the 1930s. More introductions and seed increase occurred in 1950 and seed was made available for the country aerodromes Cloncurry, Charleville and Bowen. The grass spread rapidly from Bowen and into the Burdekin Basin. It has not spread at Charleville and died out at Cloncurry.

Plant characteristics

Indian bluegrass produces many stolons (runners) that readily take root. Flowering stems are usually produced in autumn. Frost, dry times and fire can thin the stand back to the better-rooted tussock. After thinning, recovery from the crown and seedlings is rapid. These attributes make the plant quite resistant to grazing and together with its wide adaptation to soil types and vigorous, rooting stolons, it has value for soil conservation purposes.

Where it has become dense, Indian bluegrass has been observed to exclude other native grasses and herbs. Where grazing pressure is high it will continue to expand. A grazing trial near Townsville reported that the grass is not an invasive species at a low stocking rate.

Indian bluegrass appears to be less palatable and lower yielding than larger tussock grasses like buffel and black speargrass. However, it is persistent on moderate to low fertility soils where other sown grasses will not survive and native grasses have disappeared.

Local observations

Recently, Indian bluegrass was noted to be spreading rapidly into Queensland bluegrass downs and also silver-leaved ironbark/poplar box country near Fernlees following good summer rainfall. Both pastures have good stands of palatable, productive, perennial (3P) grasses.

On the bluegrass downs there is probably always 'space' for a rapid coloniser to establish. Flinders grass and Peak Downs clover are good examples. However, the cracking nature of the soils will probably limit the extent of Indian bluegrass to the original crown.

In the silver-leaved ironbark/poplar box country, the Indian bluegrass was spreading well on bare areas as well as spreading through healthy tussocks of buffel, forest mitchell and black speargrass. It is unlikely to 'choke' out the 3P grasses because, during dry times, it will decrease in size back to the original crown. Additionally, the good growing conditions have enabled it to spread though the 3P grasses.

Summary

Indian bluegrass has naturalised over vast tracts of eastern Queensland, providing good ground cover and preventing soil erosion. This is the main benefit of the grass especially where native 3P grasses have disappeared, and where other sown grasses can't survive. It is continuing to spread and once it has established it will probably persist.

However, drought and fire will decrease the size of the plant back to the original crown and it is therefore unlikely to 'choke' out healthy stands of 3P grasses. Conservative grazing management should encourage 3P grasses and prevent an abundance of Indian bluegrass.