Hyparrhenia hirta (Coolatai Grass)

Background to its discovery in the ACT

Coolatai grass was first discovered along Brindabella Road and the Barton Highway in the ACT, in around 2018.   It would have arrived on vehicle tyres or contaminated produce on passing trucks, such as hay bales. It is originally from Africa and is regarded as a significant threat to nature conservation and agricultural lands due to its ability to outcompete desirable grasses.

NatureMapr alert system plays a key role in rapid response to new detections

NatureMapr, citizen science, provides automatic alerts to Parks and Biosecurity Rangers if new sightings are made.  This allows for early control as opposed to late control. According to a NZ study late control costs 40 times more than early control. So NatureMapr saves considerable resources by facilitating early control of such invasive species.

Since Coolatai grass was first detected there have been additional sightings in Canberra and the Southern Tablelands, with automatic alerts going to Parks and Biosecurity Rangers, who have successfully contained its spread.  

As with all invasive plants, on-going surveillance and follow-up control is key to successful containment, and potential local eradication.

Description of Coolatai grass

Coolatai grass is a drought, herbicide, and fire tolerant tussock grass. It is a major weed in northern NSW, and it can smother the understorey of our region’s woodlands and grasslands.   Its most recognisable feature are its paired seed spikelets, where one spike has a stalk, and the other is stalkless.

Coolatai grass is a long-lived summer active perennial that produces short rhizomes that forms a dense grass tussock and grows to 1.5 m. It has greyish-green leaves that turn orangey-red in winter, particularly after frost. The leaves are harsh to touch. Leaf sheaths are usually hairless and keeled. The leaf blade is flat and 2-3 mm wide with the ligule 2-3 mm long and minutely toothed.

The seedhead is a ‘false panicle’ consisting of paired racemes with 5-8 awns per raceme. The paired racemes are up to 35mm long and arise from 3-8cm long flower bracts. Half the flowers are male and therefore sterile.

General biosecurity duty in NSW with additional restrictions in the Southeast region.

https://www.environment.act.gov.au/__data/assets/pdf_file/0010/1144486/Coolatai-Grassv103.11.17.pdf

http://weeds.dpi.nsw.gov.au/Weeds/Details/179