Whisky grass

Whisky grass is present in the ACT.

About the pest

Whisky grass (Andropogon virginicus) is regarded as an environmental weed in the ACT, New South Wales and Queensland. It prefers very open sunny areas and is particularly common along tracks and roadsides.

Why it is a problem

Whisky grass, unlike many exotic weeds, is known to invade native plant communities that are extremely deficient in nutrients. It also aggressively outcompetes native flora for space and light. The dense tussocks and root systems can also lower soil evaporation causing accelerated erosion.

In autumn, whisky grass dies off, leaving dense, dry, orange-brown stands that are highly flammable. It burns much more intensely than native vegetation, altering natural fire regimes and fuelling dangerous bushfires.

What to look for

• Older whisky grass plants are tufted grass usually growing 0.5–1 m tall.
• The older stems and leaves turn reddish-brown or brownish-orange in colour during summer.
• Its elongated leaves (10–40 cm long and 2–5 mm wide) can be either flat or folded where the leaf sheath meets the leaf blade. Its flower-spikelets fall off entirely at maturity, usually with numerous long white silky hairs.

How it spreads

Whisky grass spreads almost exclusively through its prolific, wind-borne seeds. It creates vast quantities of light, fluffy seed heads in autumn that are easily carried long distances by the wind, water and passing animals.

Human activity, such as vehicle movement, slashing and agricultural transport, also drives its spread.

Report sightings