Image: chilean needle grass seed panicle.
What is Chilean needle grass?
Chilean needle grass is a perennial grass native to South America. It is a serious weed of pastures and native grasslands.
Chilean needle grass is a declared weed under the Tasmanian Biosecuriy Act 2019 and associated Regulations. The importation, sale and distribution of Chilean needle grass are prohibited in Tasmania.
Chilean needle grass is also a
Weed of National Significance (WONS).
How to identify Chilean needle grass
Chilean needle grass is a perennial (long-lived) tussock-forming grass growing to 1 metre in height. The leaves are 1 to 5 mm wide, flat and strongly ribbed on their upper surface, with leaf edges that are rough to touch.
The flowering seed heads are a distinctive purplish colour and the seeds are very sharp at the point. Chilean needle grass flowers mainly from September to December but can flower year round. Seed is formed about one month after flowering and most seed has been dropped by February. Seeds mainly germinate in autumn and spring.
Spread is by seed. In addition to the normal flower (panicle) seeds, Chilean needle grass produces hidden seeds which are formed in the nodes and bases of the flowering stems. These 'stem seeds' are self-fertilised and account for about one-quarter of total seed production. They enable the plant to survive despite grazing, slashing and fire.
Chilean needle grass seeds can persist in the soil for many years even if further seed input is prevented. The seeds are spread by farm machinery, clothing or livestock, by road-side mowing and earthmoving equipment, and by floodwaters.
See the Nassella species identification comparison table below for more information on identification.
Chilean needle grass in Tasmania
Currently Chilean needle grass populations are found in urban areas around Hobart, particularly the Eastern shore, where it can be found along roadside reserves and nature strips. It is also known in rural areas in the south of the state and on Flinders Island.
Chilean needle grass is a vigorous competitor and poses a significant threat to native grasslands and agricultural enterprises in Tasmania. It can reduce pasture productivity, contaminate crops and hay, and seeds can injure livestock, in particular sheep.
This species is a very high priority for eradication in Tasmania.
If you locate Chilean needle grass anywhere in Tasmania, or if you find a plant that you think could be Chilean needle grass, immediately contact Biosecurity Tasmania on 03 6165 3777.
What is the legal status of Chilean needle grass in your area?
See also
Chilean Needle Grass Control Guide
Spread of Chilean needle grass
Chilean needle grass panicle seed is large and heavy and will not travel very far in the wind, maybe only a few metres.
Seed spread is facilitated by the long, twisting awn and the sharply pointed seed head which together allow the seed to penetrate and 'burrow' into animal coats, fleece and clothing.
Chilean needle grass seed can also be carried in mud on the hooves of livestock, machinery and implements, on vehicle tyres, in contaminated hay and on firewood.
Chilean needle grass panicle seed can be dispersed by water along creeks and drainage channels.
Avoid the introduction of Chilean needle grass
Preventing the invasion of Chilean needle grass is the cheapest and most effective means of control.
Learn to identify Chilean needle grass, regularly check for it and act immediately to remove it.
Regularly monitor known Chilean needle grass infested areas.
Appropriately dispose of any panicle seed collected.
Encourage the growth of competition in infested areas.
If possible avoid working in an area infested with Chilean needle grass until it has been controlled.
See the
Weed and Disease Planning and Hygiene Guidelines for detailed information on how to wash-down equipment and personnel to reduce the chance of spreading Chilean needle grass.
Control options
Before undertaking control works confirm that the species you intend to control is in fact Chilean needle grass as the plant you are dealing with may be a native Tasmanian grass.
The following information is for the control of small populations of Chilean needle grass in urban environments including roadside reserves and native grassland situations.
For identification and advice on the control of populations in pasture situations or larger infestations contact Biosecurity Tasmania on 03 6165 3777.
Physical removal
Small infestations and isolated Chilean needle grass plants can be chipped out with a mattock preferably before the plants set seed. Ensure that the base of the plant and as much of the root as possible is removed.
Do not chip out large patches of Chilean needle grass where a seed bank has built up: any soil disturbance will cause the germination of seeds.
Chemical control
Nassella species identification comparison table
Status
| Introduced Declared; an Alert List Weed
| Introduced; Declared;
an Alert List Weed. | Introduced; Declared; an Alert List Weed.
| Introduced; Declared;
Weed of National Significance.
| Introduced; Declared;
Weed of National Significance
|
Form
| Tussock
| Tussock
| Tussock
| Tussock
| Tussock
|
Seed
(outer casing of seed, the 'glume', removed to reveal detail.)
| | 
|
| 
|
|
"Corona", the collar at seed base
| Present
| Present
| Present
| Present
| Absent
|
'Awn", the bristle like seed tail
| 45-85mm double bent firmly fixed to seed coat
| 35-40mm
Twisted and bent
| 35-60mm long
Bent twice with 10-20mm to first bend
| 25-35mm Straight or double bent.
Firmly fixed seed coat
| 10mm
Straight
Readily detached from seed coat
|
'Cleistogenes', or stem seeds
| Absent
| Present
| Present
| Present
| Absent
|
'Ligule', the flap at leaf base
| |
| 
|
 |
|
Overall dimensions
| 0.5-1.0m high
0.3 -0.5m across | to 1m high
0.3m across
| 1-1.5m high
0.2 -0.5m across
| 1-1.5m high
0.3 -0.6m across
| 1m high,
0.6m acros
|
* Images in table:
© 2003 Weed Management Guides, Lobed needle grass, Chilean needle grass, Serrated tussock, C'wlth Dept of the Env't & Heritage.
© Chilean Needle Grass & Serrated Tussock Ligule photos: Harry Rose (Wikimedia).
|