Weed of the Month: Coolatai grass Hyparrhenia hirta

Flora, The Scoop, Weed of the Month

Regional Priority Weed Objective – ASSET PROTECTION

An invasive drought, fire and herbicide tolerant tussock forming perennial grass.   It is found in all Australian states and territories. The main infestations on the East coast were south-eastern Queensland, north eastern NSW but occurs widely across the Hunter and is spreading quickly.  Coolatai wasn’t declared noxious in the Hunter before the development of the Hunter Regional Weeds Committee.  Contact your local Weeds Coordinator to ask for a higher level of control where we need it most- primarily along roads to help halt the spread.  


It is one of the few perennial grasses capable of invading undisturbed natural ecosystems and is a major threat to natural biodiversity in stock routes, nature reserves and National Parks.  It is problematic for graziers- readily invades pastures and dominates them, particularly where ground cover is low soil fertility.  Failure to appropriately manage a Coolatai grass dominated pasture will see a monoculture of tall rank growth of low digestibility and protein. 

Native species that might be confused with Coolatai grass- Barbed wire grass (Cymbopogon refractus); Kangaroo grass (Themeda australis); Redgrass (Bothriochloa macra). 

The most obvious distinguishing characteristic of Coolatai grass is the paired racemes with 5-8 brown awns per raceme. The racemes are soft to touch compared with barb wire grass and kangaroo grass.  

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