Quick Facts

Quick facts

  • Originally from South America, Chilean Needle Grass (Nassella neesiana), a Weeds of National Significance, is a perennial tufted grass 11.5 m tall, highly invasive with serious impacts on the environment, agriculture and the economy.
  • It poses a threat in cool to warm temperate, to sub-tropical areas, preferring areas with rainfall over 500 mm, growing in rich to poor degraded soils, readily invading pastures and native grasslands excluding desirable species.
  • Chilean Needle Grass builds up a large and persistent seed-bank in the soil, producing abundant flowering seeds, and hidden stem seeds, found at the base of the plant, and in the joints (nodes) of the stem. Stem seeds account for 1/4 of all seed production.
  • Chilean Needle Grass has much reduced nutritional value relative to improved pastures, and if animals are present in summer when the sharp flowering seeds are produced, these can injure and damage animals, downgrading produce.
  • Rehabilitation of infested land is very difficult, for best results, combine herbicide application with physical removal, crop rotation, pasture sowing and grazing management (short duration, high intensity) (CRC 2003).
  • All control programs should aim to reduce the amount of seed produced, with prevention and early detection the most cost-effective form of weed control, with quarantine and good hygiene within infestations preventing spread.


What Does It Look Like?

What is it?

Chilean Needle Grass (Nassella neesiana), is a perennial long-lived, very hardy, tussock-forming grass that grows in dense clumps to 11.5 m in height, named for its sharp-pointed needle-like seeds. Chilean Needle Grass has an extensive fibrous root system making it very difficult to pull from the ground. Its leaves are about 300 mm long, flat to 5 mm wide to somewhat in-rolled, strongly ribbed on their upper surface, sometimes sparsely coarsely hairy, with edges that are rough to touch (particularly in one direction) due to stiff marginal hairs. Leaves have a smooth membranous ligule (a small structure arising at at the base of the inner junction of the leaf and stem, wrapping around the stem), up to 3 mm long (sometimes almost absent on lower leaves), which extends across the leaf and is bordered by two small tufts of erect hairs either side which are easily seen when the leaf is pulled away from the stem (Iaconis 2004).

The Inflorescence (flowering heads called panicles) or flowering seed heads, are loosely branched, open, growing to 100–400 mm long. Flower heads are normally exerted (mostly, sometimes fully extending beyond leaves). The flowering heads contain many whorls of 2-3 or more branches, each with a single flower at the end, or these branch further with flowers at the end. Each flowering stem can produce 50–200 or more flowers with each plant producing 1,000s and 1000s of flowers developing into seeds. With-in heavily infested areas a square-metre can produce more than 20,000 seeds per year. The seeds are always surrounded by papery thin scales (called glumes), 16-18 mm to sometimes 20 mm long, sub-equal (with one glume slightly longer than the other), deep to light purple in colour, acuminate (tapering in to a point). Seeds have a relatively long awn, (a hair / bristle like structure) 60–90 mm long that is exerted beyond the glumes. 

Chilean Needle Grass is unusual in producing two types of seeds: besides the normal seeds produced from flowering seed heads; seeds are also produced in two location in stems; called stem seeds – with seeds hidden in the nodes (swellings along the stems that give rise to leaves) throughout the plant; and, basal seeds – with seeds hidden at the very base of the plant in the stems at soil level. These 'stem and basal seeds' are self-fertilised and account for about one-quarter of total seed production. They enable the plant to reproduce despite grazing, slashing and mild fire (CRC 2003).

The flowering head seeds of Chilean Needle Grass are 6-10 mm long to 0.7-1 mm wide, having a sharp hard point at the base called a callus, 2–4 mm long that is weakly bent at the tip, with with a beard (tufts of silky hairs) extending in part up the seed for 1/4  to 1/3 the length of the seed. The seed is slightly  bumpy to warty to rough and pale cream-brown at maturity (when ripe). The awn 60–90 mm long, is twice to three times bent, 15–30 mm to the first bend, scabrous (with short stiff hairs) to pubescent (having soft hairs), is attached to the centre back of the seed. The awns often form a tangled mass at maturity. At the junction of the awn and the lemma, there is a characteristic raised crown 11.5 mm long with small teeth (Laconis 2004). This is known as a corona and it encircles the base of the awn (illustrated by Jacobs & Everett 1993; Walsh 1994; Sainty & Associates 2002; Jessop et al. 2006). Description based on Jacobs & Everett (1993), Walsh (1994), Sainty & Associates (2002), CRC (2003), Laconis (2004) and Evereyt et al. (in preparation).

Recognition: This species can normally be recognized by the combination of the following characters; large seeds to 10 mm long with distinct corona to 1mm long; robust (wiry) awn to 60-90 mm long bent 2-3 times; tussock large forming plant to 1-1.5 m tall with rough leaf edges; smooth membranous ligule to 3 mm long bordered by two small tufts of erect hairs on either side; many flowering heads produced, mostly exerted (above) the leaves.  

For further information and assistance with identification of Chilean Needle Grass contact the herbarium in your state or territory.

Flower colour

green and purple.

Growth form (weed type/habit)


Where it currently grows? Preferred habitat

Chilean Needle Grass grows in temperate regions with annual rainfall greater than 500 mm. It can thrive in a wide range of soils and conditions from fertile to poorer and degraded soils and has the potential to be very invasive over a large part of the country in both pasture and native vegetation.

Although it occurs mainly in pastures and grassy woodlands, on roadsides, and along creeks and rivers, it is increasingly invading native grasslands (CRC 2003). It tolerates drought and heavy grazing (CRC 2003), and is able to establish on even the hardest bare sites on disturbed ground (Jessop et al. 2006).

Are there similar species?

Chilean Needle Grass is similar in appearance to the Native Spear grasses (Austrostipa species). They all have sharp seeds with a long curved or bent awn and hairy tip, and may appear red before drying to a straw colour.

Before flowering, green leafy plants of Chilean Needle Grass can be mistaken for many other winter-green species, especially Austrostipa, Rytidosperma [as Austrodanthonia] and Festuca. If you look closely, you can see hairs along the leaf surface of Chilean Needle Grass, in contrast to the hairless leaves of Fescue.

Chilean Needle Grass also has a small tuft of hairs at the junction of the leaf blade and the leaf sheath which Fescue does not have.

The leaves of Chilean Needle Grass are much coarser and wider than those of Rytidosperma [as Austrodanthonia] (CRC 2003).

The most distinctive feature of Chilean Needle Grass seed is the corona (raised crown with small teeth) at the join of the seed body and the awn (CRC 2003). Differences from other Nassella species are illustrated by Jacobs & Everett (1993), Walsh (1994), Wheeler et al. (2002) and Richardson et al. (2006); and Muyt (2001).

See link: https://www.uppercampaspelandcare.org.au/wp-content/uploads/needle-grass-web-LR-1.pdf

Why Is It A Weed?

What are its impacts?

Chilean Needle Grass (Nassella neesiana) is a Weed of National Significance. It is regarded as one of the worst weeds in Australia because of its invasiveness, potential for spread, and economic and environmental impacts. It is closely related to another Weed of National Significance, Serrated Tussock (Nassella trichotoma) (CRC 2003). Chilean Needle Grass affects sown pasture, native grasslands and urban and amenity areas of southern and south-eastern Australia.

Agriculture: It is relatively unpalatable and lower in nutrients than improved pastures, reducing farm productivity by displacing more desirable pasture species. Heavy infestations can decrease productivity by as much as 50% during summer (CRC 2003). It can completely overrun pastures resulting in a canopy cover of up to 60%, which leads to a substantial reduction of stock carrying capacity during late spring and summer when the weed produces large quantities of unpalatable flower stalks (Grech et al. 2004).

The sharp seeds have a natural twisting mechanism that cause seeds to lodge into fleece, skin, eyes and ears of livestock in response to changes in humidity (Weeds Australia). In New Zealand and eastern states of Australia the seeds have been found to move through the skin and into the body muscles, causing abscesses and downgrading carcasses, and even rendering them unsalable (Weeds Australia, no date). These impacts can significantly affect the value of agricultural products.

Native ecosystems: Chilean Needle Grass is possibly the worst environmental weed threatening endangered indigenous grasslands in south-eastern Australia (Laconis 2004). Chilean Needle Grass can rapidly invade disturbed soils and degraded ecosystems. It is also invading grassy open woodlands and riparian vegetation in many areas. Chilean Needle Grass will out-compete and displace native grasses and herbs, interfere with re-vegetation programs and once established are difficult to manage. Degradation of native habitats including grassland and other habitats will have impacts on native birds and other fauna.

Urban areas:The seeds of Chilean Needle Grass are also known to cause discomfort to dogs and humans, thereby restricting human access in recreational and other areas (Weeds Australia), and is a weed of amenity and neglected areas, parks, gardens, reserves and sporting grounds. 

How does it spread?

Chilean Needle Grass disperses and grows from seed, and not by vegetative structures such as rhizomes or perennial roots. Plants in a square metre can produce more than 20,000 seeds per year. The resulting seed-bank can persist for many years, even if further seed input is prevented.

Chilean Needle Grass, can be very effectively spread on farm machinery, clothing or livestock. It will attach to vehicles and machinery, for example, cultivation implements, vehicle tyres, slashing equipment, tractors, spray units, mowers and slashers, and bottom of vehicles, making it possible to spread over large distances. Seed has also been spread along roadsides and other grassy areas by mowing and earth-moving equipment. Stem seeds can be spread by most of these methods. It may also be transported by moving soil. Seed transported or buried in soil by cultivation can remain dormant for several years and produce seedlings after subsequent soil disturbance. Floodwater will move seed downstream (CRC 2003).

It can also be spread by animals when it catches on the fleece of sheep or coats of livestock, or be picked up in mud on their hooves. It can also spread in produce such as fodder, grain, hay.

People can spread it when the seeds attach to clothes, especially socks and pants.

What is its history in Australia?

It is thought that Chilean Needle Grass was imported to Australia as a contaminant of wool or fodder from South America (Weeds Australia, no date). It was first identified in Australia in 1934 (from the Melbourne suburb of Northcote). In addition, a couple of samples were imported in 1945 and 1951 as a potential pasture species, as part of the Commonwealth Plant Introduction program (Cook & Dias 2006). It appears to have spread very slowly until the late 1970s and has only recently been recognised as a serious weed (CRC 2003). The earliest known collection in New South Wales was from Glen Innes on the New England Tablelands in 1944; in South Australia it was first recorded from Lucindale in 1988; and from Queensland in 1998 (Weeds Australia, no date).

How To Manage It?

Best practice management

Chilean Needle Grass is extremely vigorous and competitive. Land managers need to know how to identify it and take prompt action if it is discovered. Management options in established infestations will depend on land use and may include crop rotation, pasture sowing, herbicide control, cultivation,  grazing, and other cultural management options. For best results a combination of options needs to be used (CRC 2003).

Chemical control: Herbicide treatment can be effective. Spot spraying is effective when used on individual plants and small infestations. For large infestations boom spraying as part of integrated weed management techniques can be useful. For up-to-date information on which herbicides are registered to control Chilean Needle Grass and the best application methods and dosages, contact your state or territory weed management agency or local council. Also see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au . Permits from state or territory Environment Protection Authorities may be required if herbicides are to be sprayed on riverbanks.

Non-chemical control: Physical control: Hand weeding or chipping is very effective on single plants or small patches. Plants cannot be left to dry in the paddock because of the basal and stem seeds. The whole plant needs to be destroyed.

Mowing and slashing may reduce seed set in the flower heads but it can actively disperse stem seeds if machinery is not kept clean. Mowing with a catcher mower during flowering will reduce seed set but it will not remove the basal and stem seeds. Clippings must be burnt and the mower must be thoroughly cleaned before it is used elsewhere (CRC 2003). Maintaining weed-free machinery and equipment is very important in preventing further spread of Chilean Needle Grass. Check machinery moving onto your property and wash down vehicles and machinery in the same area to allow easy follow-up control of any seeds that may germinate. Don't buy hay, stock feed, or crop and pasture seed from infested areas.

Competition and management: Control may be achieved using cultivation. Cultivation of the soil encourages seeds to germinate and these can be controlled. Sowing a dense pasture or crop will reduce the amount of Chilean Needle Grass that germinates. Rotational cropping and a mix of cultivation and herbicide application can be used to prevent seedling.

Grazing by animals at the correct time of year when no flowering seed-heads are present can be used. For larger areas larger mobs and a cycle of short duration of high intensity grazing followed by long rest periods offers the benefit of better pasture, fewer weeds and better livestock returns (CRC 2003).  However, Chilean Needle Grass is of lower nutritional value than improved pastures and once it starts flowering the nutritional value decreases further. In addition, the sharp mature seeds attach to animals coats and can penetrate lips, skin and flesh causing harm to animals, downgrading and reducing the values of produce, be it wool or meat.

Mulching: Suitable for small infestations in native or urban areas, or larger infections in agricultural situations. Mulching is the the application of material over the ground such as straw, wood chips, carpet or plastic sheeting will prevent the growth of all plants, including weeds and beneficial plants. Organic mulch should be 100 mm thick, regularly topped-up as this reduces over time and used with other control methods to remove any unwanted plants that germinate.

Fire: The use of fire has a management tool has been used to burn-off and kill flowering and stem seeds in large infestations.  Other follow up controls methods are required to prevent regrowth and germination of Chilean Needle Grass. 

Biological control: Research on the rust fungus Puccinia nassellae was conducted in Argentina to ensure that it is safe and will not attack any other species if released in Australia. It did not prove to be a successful biological control. No useful biological control agents are available in Australia.

With any of the control programs it is vital to ensure that any Chilean Needle Grass seedlings are prevented from flowering. For further information on management and control of Chilean Needle Grass see Agriculture & Resource Management Council of Australia & New Zealand, Australian & New Zealand Environment & Conservation Council and Forestry Ministers (2000), Muyt (2001), CRC for Australian Weed Management (2003, both references), Dellow (2003), McLaren (2003), Storrie & Lowien (2003), Grech et al. (2004), Pritchard (2004) and Weeds Australia.

Does it have a biological control agent?


When does it grow? (lifecycle/growth calendar)

Seeds mainly germinate in autumn and spring, but germination can occur at other times of year given adequate moisture and suitable temperature. Seedlings grow quite slowly but have a very high survival rate and can produce flowers in their first season.  Vegetative growth occurs in autumn winter and spring.

Chilean Needle Grass flowers mainly in spring from September to December or in autumn from March to May, but it can potentially flower year round in favuorable conditions with adequate water availability and suitable temperatures. Seed is formed about one to two month after flowering and most flowering seeds detach or are dropped by the plant by February (CRC 2003).

Where Is It Found?

Which states and territories is it found?


What areas within states and territories is it found?

Its known range extends from the south-east Queensland, the Northern Tablelands of New South Wales, along the Great Divide and through Victoria to south-eastern South Australia. It is well established in large areas of New South Wales, the Australian Capital Territory and Victoria.

Isolated but expanding infestations have been recorded in South Australia, southern Tasmania and the Darling Downs Region of southern Queensland (CRC 2003). Records in South Australia include areas near Lucindale, in the Northern and Southern Lofty regions, respectively (Jessop et al. 2006).

It has been eradicated from the one known site in Tasmania, in Hobart, and this site is subject to ongoing monitoring (Department of Primary Industries and Water, Tasmanian Government 2007).

Where does it originate?

Chilean Needle Grass is native to South and America, including Ecuador, Bolivia, Chile, Argentina, Uruguay and southern Brazil (Sainty & Associates 2002). There are about 80 species of Nassella from the Americas. None of the seven Nassella species occurring in Australia are native (Everett et al. in preparation). It is also naturalised and often a weed in Europe, the Americas, South Africa and New Zealand.

National And State Weed Listings

Is it a Weed of National Significance (WONS)?


Where is it a declared weed?

Declared in all States and Territories.

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?


Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?


Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Nassella neesiana

Other scientific names (synonyms)?

  • Stipa eminems Nees
  • Stipa neesiana Trin. & Rupr.

Does it have other known common name(s)?

Chilean Needle Grass

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