Perennial Mission Grass is well-established across the Top End of the Northern Territory. Its stronghold is in the Darwin-Daly region, but it is also found in north-east Arnhem Land, on the Tiwi Islands and as far south as Daly Waters. Originally from tropical Africa, it was brought to Australia as a pasture species that is palatable when young or well-fertilized, and because of its ability to colonise disturbed sites. Though officially released in Queensland, its escape into the wild in the Northern Territory at Berrimah in the 1970s was apparently accidental.

Mission Grass - Cenchrus polystachios

Photo: © Jeremy Garnett


A coloniser of disturbed sites, Perennial Mission Grass occurs along roads and tracks, but is less abundant in the more extensive landscape. Its main impact is through its high fuel loads, which are substantially greater than those of most native grasses. Mainland species that could be threatened by fires fuelled by Perennial Mission Grass include the woodland plants Armstrong's Cycad and Glenluckie Helicteres, and plants growing at the edge of monsoon rainforests, such as the Malaxis ground orchid. On the Tiwi Islands, Perennial Mission Grass is a potential threat to Butler's Dunnart, particularly if it results in incineration of the logs and litter in which the dunnarts shelter. By both altering the habitat and obstructing the visibility of ground-dwelling prey, Perennial Mission Grass may reduce food available to Masked Owl, both on the Tiwi Islands and the mainland.


Perennial Mission Grass is a declared weed in the Northern Territory, where its growth and spread must be controlled. It is listed as a high impact weed in the Field Guide to Assessing Australia’s Tropical Riparian Zones and a Key Threatening Process to biodiversity in Northern Australia.


Recommended practices include keeping machinery free of Mission Grass seed to prevent spread beyond infested areas; not using Mission Grass in hay; containing existing large areas; and eradicating small outlying infestations. Individual clumps of Mission Grass can be dug out with a hoe or mattock. Effective control is achieved by burning Mission Grass before flowering in the early dry season, followed by glyphosate application early in the following wet season.