Chilean needle grass: declared pest

Page last updated: Monday, 11 May 2020 - 1:16pm

Please note: This content may be out of date and is currently under review.

Chilean needle grass (Nassella neesiana) is a declared pest in Western Australia (WA). This article describes the nature of the plant with links to requirements land owners/occupiers must adhere to and pest control methods.

Form: grass — perennial

Status: not known to be present in WA, if found please report

Native to South America, Chilean needle grass is a Weed of National Significance in Australia.


Chilean needle grass, is an erect, perennial tussock-forming grass (up to one metre tall) that grows in dense clumps. It is a strong competitor in agricultural, natural and urban environments.

Leaves: Hairless or sparsely hairy leaves, mid- to dark green, 10-30 centimetres long, one to five millimetres wide, flat or partly in-rolled and strongly ribbed on their upper surface, with leaf edges that are rough to touch. A small tufts of erect hairs where the leaf blade joins the stem.

Flowers: The inflorescence is a loose panicle, up to 40 centimetres long, with a distinctive purplish colour. Flowering stems are erect or arching, slightly rough to the touch.

Seed: Pale brown when mature, mostly eight to ten millimetres long, with an awn 60-90 millimetres long, with a seed head to 40 centimetres long. The seed is sharply pointed and finely hairy at the tip, six to ten millimetres long, narrowing into a long (40-90 millimetres) awn at the upper end. The best distinguishing feature is the presence of a collar of short hairs at the point where the long awn attaches to the seed.

Chilean needle grass’ resilient reproductive system produces three types of seed: panicle seeds (main seed head) and stem and basal seeds, with each plant producing more than 25 000 seeds in a season.

Agriculture and economic impact

Chilean Needle Grass affects both sown pasture and native grasslands of south-eastern Australia. It is relatively unpalatable and reduces farm productivity by displacing more desirable pasture species.

Declared pest category

The Western Australian Organism List (WAOL) contains information on the area(s) in which this pest is declared and the control and keeping categories to which it has been assigned in Western Australia (WA). Search for Chilean needle grass in the WAOL using the scientific name Nassella neesiana.

Requirements for land owners/occupiers and other persons

Requirements for land owners/occupiers and other persons if this pest is found can be sourced through the declared plant requirements link.

Search > detect > report

MyPestGuide™ Reporter
via app or online
(Select 'Send report to MyWeedWatcher' from menu)

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080

Control method

Report the presence of this organism before undertaking a control measure. Control methods for this declared plant can be found through the Chilean needle grass control link.

Contact information

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080
Technical support - MyPestGuide®