Coolatai project
Noxious weeds

The project

The Northern Rivers Catchment Management Authority (NRCMA) has funded a joint project between Macleay Landcare, Kempsey Council and National Parks & Wildlife Service (NPWS) to raise the awareness of Coolatai grass in the Macleay valley, and to treat Coolatai grass infestations threatening Hat Head National Park.

The project will run in 2010 and 2011 and involves:

  • Coolatai grass workshops for industry groups and community members,
  • Information sheets,
  • Presentations to community groups,
  • Quarantine and control measures on the roads in and surrounding Hat Head National Park.

As a part of the project, some road sides will be quarantined for the duration of the project. This is to ensure that vehicles and pedestrians do not spread seed from known Coolatai populations into new areas. Please look out for the “Coolatai Quarantine” signs and refrain from entering these areas.

Worker washing down truck

Quarantine is extremely important when controlling Coolatai.

Always wash down vehicles that have been in Coolatai areas as seeds stick easily to grills, tyres and undersides of cars and bikes

Coolatai Grass

Coolatai Grass - the new coastal threat

A native of Africa, Coolatai grass (Hyparrhenia hirta) has taken over large areas of North Western NSW and tablelands and is now spreading on the coast. Originally it was introduced into Australia for soil stabilisation and as a pasture. It has many qualities that make it an undesirable species.

The threat

Coolatai grass can spread to new areas very quickly!

  • It can quickly out-compete other ground covers and grasses forming a dense monoculture.
  • It is self pollinating. It only takes one seed to germinate for a new population to start.
  • During its seeding phase, the plant produces thousands of tiny, sticky seeds which adhere readily to animals, farm machinery and motor vehicles.
  • Seeds move easily in water.

Coolatai Grass causes serious ecological damage within national parks

  • Coolatai grass displaces native plant species, and threatens the understorey of native plant communities including native grasslands and grassy woodlands. On the coast it is of great concern that it will invade the threatened ecological community of Themeda Grasslands, which occur on many headlands.
  • The invasion of native plant communities by exotic perennial grasses is a key threatening process under the Biodiversity Conservation Act 2016 (NSW).

Coolatai Grass is unpalatable to stock

  • Once the grass has reached flowering stage, it becomes unpalatable to stock, thus allowing further seed distribution.
  • Very high stocking rates can keep Coolatai grass in check in pastures, however this may lead to other land degradation issues.

Coolatai grass is a major fire threat

  • The abundance of dry stalks and leaf matter cause Coolatai grass to burn with intense heat, and in an uncontrolled fire event can cause severe damage, and threaten livestock and human life.
  • A Coolatai grass fire emits excessive smoke, which can also create an extremely hazardous situation for motorists.
Coolatai grass beside road Coolatai grass in national parkCoolatai grass in drainage line Coolatai grass on roadsides, in national park and in drainage lines


Description: A perennial tussock grass up to 2m tall, its main growing period is late spring and summer. Coolatai grass can be confused with similar looking native grasses, e.g. Lemon scented grasses (Cymbopogon species), Kangaroo grass (Themeda australis), Barbed wire grass (Cymbopogan refractus) and Red-leg grass (Bothriochloa macra).

Flowers/seedhead: A pair of grey-white flower racemes (spikes) up to 5cm long forms a “V” at the end of the flowering stalks. Each raceme has 5-7 paired spikelets with a single brown awn on each pair. Usually Coolatai grass flowers in late spring and summer, but in frost free areas may flower all year round.

Leaves: 2-4 mm wide, green to blue-green, rough to touch; no smell.

Illustration of Coolatai grass
Coolatai grass


Every effort should be made to prevent Coolatai grass from becoming established in new areas.

Worker hand pulling Coolatai GrassHand pulling or grubbing and bagging is a very efficient way of controlling small pockets of Coolatai grass

Manual removal: Small isolated infestations should be removed before they seed. When carrying out manual removal, ensure the basal crown is also removed. Coolatai Grass will rapidly resprout from a basal crown after defoliation or dormancy.

Chemical use: Mature plants are difficult to kill as the remaining old dry growth prevents good herbicide contact. Manual removal of seedheads and slashing 1-2 weeks prior to spraying is recommended so that herbicide is applied to new growth. Several applications may be required before the plant is killed (see Herbicide table below).

Fire: Fire can be used to remove dead matter before applying herbicide to regrowth. The affects on surrounding vegetation needs to taken into account as Coolatai Grass is highly flammable.

Slashing & cutting: If infestations occur at sites that require slashing or mowing for management purposes (such as roadsides), ensure work is carried out before seeding and always clean machinery to prevent spread.

Biological control: There are no biological control agents available for Coolatai Grass

Grazing: Grazing encourages growth of Coolatai Grass. To achieve an acceptable level of control, grazing pressure needs to be very high, to ensure seeding phase is not reached.

Recommended rates for herbicide application

Important: Always read the label - always read and follow permit directions

Pesticides must only be used for the purpose for which they are registered and must not be used in any other situation or in any manner contrary to the directions on the label. Never use an herbicide in any way contrary to the label recommendations.

Chemical Rate: Spot/boom Comments
Glyphosate 360 g/L
(various trade names)
2.0 L in 100L of water Apply to actively growing plants before flowering. Wet to run-off, ie. 1000-2000 L/ha. Spray 2-3 times Sep to May
Glyphosate 360 g/L
(various trade names)
2.0 L glyphosate Apply to actively growing plants before flowering. Spray Jul to Oct (addition of fluproponate is most effective during spring)

Spot spray: Apply wet to run-off, ie. 1000-2000 L/ha

Broadacre ground spray situation: Perennial pastures and non-crop situations including rights-of-way, bushland, forests, reserves and roadsides ie glyphosate: up to 6L/ha; flupropanate: up to 3 L/ha

plus plus
Flupropanate 745 g/L
eg Tussock Herbicide®
200 mL flupropanate in 100 L of water
Logos of the Coolatai Project sponsors

Disclaimer: The information contained on this website is based on knowledge and understanding at the time of writing. However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of North West Weeds or the user’s independent adviser.