Quick Facts

Quick facts

• Originally from South America, Lobed Needle Grass (Nassella charruana) is an invasive, unpalatable tussock grass to 1 m high.
• Dense infestations exclude other more desirable species.
• It has very sharp seeds which are easily spread by attaching to clothing, fur or machinery.
• It is distinguished by having two distinctive pale brown to white lobes at the top of the dark brown lemma enclosing the seed.
• In Australia it is limited to a few small infestations on the northern outskirts of Melbourne but it may easily spread without continued vigilance.

What Does It Look Like?

What is it?

Lobed Needle Grass (Nassella charruana) is a Shortly rhizomatous, tufted perennial, spear grass growing to about 1 m high. The leaves are rough to the touch, narrow and rolled inwards, to 60 cm long and 2 mm wide, and, like other tussock grasses, grow from the plant base, with a leaf-sheath rolled around the stem where the blade meets the stem. The ligule is a membranous small  flap to 1 mm long at the junction of the leaf blade and the leaf sheath on the stem. The ligule can be located by tracing a leaf down to where it joins the sheath and bending the leaf back at this point.

The shiny branching flower heads (called panicles) grow to 30 cm long, sometimes partly retained at the base in the upper leaf sheath. There is a single flower in each spikelet composed of a floret (flower) enclosed by two glumes (pointed bracts ) 14–18 mm long, yellowish white or straw-coloured. Contained within the glumes is a lemma which becomes the husk of the seed,  

The seed (fruit) has a body and awn. The body of the seed is the lemma, is 5–7.5 mm long and less than 1 mm wide attached to a awn (the long bristle-like tip of the seed), with a corona (or crown where the lemma meets the awn). The awn is 4.5 to 9 cm long, twisted in the basal section and is once or twice bent, twisting in the lower one-third, scabrous. The corona (or crown where the lemma meets the awn) is 3.5–5 mm long, membranous, minutely fringed apically. The point of the lemma or seed. (Sainty & Associates 2002; Faithfull & Gillespie 2004; Richardson et al. 2006; VivFlora 2016).

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

Flower colour

White

Growth form (weed type/habit)

Grass

Where it currently grows? Preferred habitat

Stipoid grasses (such as the Nassella species) generally invade sites that are already highly degraded, especially land with higher fertility soil that has been used for grazing or farming. As well as growing in urban areas and on rural roadsides, Lobed Needle Grass has invaded open woodlands and native and introduced grasslands including grassland dominated by four other Nassella species. It grows mainly in open areas, in direct sunlight or light shade, on clay soils – its preferred soil type in South America. It is tolerant to waterlogging and appears to prefer wet depressions, but it also occurs on stony rises (CRC 2003).

Are there similar species?

Lobed Needle Grass is hard to identify because it is similar to native spear grasses (Austrostipa species and Poa species) and other Nassella species. They all have sharp seeds with a long curved or bent awn and hairy tip. However, Nassella species have strongly overlapping margins of the lemma, which make it difficult to open the mature seeds. Also, the seeds of most Nassella species (except Serrated Tussock) have a corona, a raised crown at the joining of the seed body and the awn and have membranous ligules (found on the stem where the leaf bald meet the stem). The corona is absent from Austrostipa species (CRC 2003) and Austrostipa and Poa species either lack ligules on their leaves, or have ligules that are fringed with hairs (Queensland Governemnt 2016).

In Lobed Needle Grass the corona is much longer than in most other Nassella species and is about 3.5 mm long. If not in seed, the ligule can be used to assist in identifying Lobed Needle Grass; it is short (about 1 mm), transparent and has only a few short hairs (CRC 2003). Queensland Government (2016) list the differences between introduced Nassella species as:

Lobed Needlegrass (Nassella charruana) has seeds with relatively long awns (more than 45 mm long) and a long corona (5–6 mm long). Its flower spikelets are relatively large (16–18 mm long) and it does not produce stem seeds (i.e. cleistogenes).

Chilean Needlegrass (Nassella neesiana) has seeds with relatively long awns (more than 45 mm long) and a short corona (less than 1.5 mm long). Its flower spikelets are relatively large (10–22 mm long) and it produces stem seeds (i.e. cleistogenes).

Cane Needlegrass (Nassella hyalina) has seeds with relatively short awns (20–45 mm long) and a short corona (less than 1.5 mm long). Its flower spikelets are relatively small (5–12 mm long) and it produces stem seeds (i.e. cleistogenes).

Texas Needlegrass (Nassella leucotricha) has seeds with relatively long awns (more than 45 mm long) and a moderately-sized corona (1.5–2.5 mm long). Its flower spikelets are relatively large (10-17 mm long) and it produces stem seeds (i.e. cleistogenes).

Short-spined needlegrass (Nassella megapotamia) has seeds with relatively long awns (more than 45 mm long) and a short corona (less than 1.5 mm long). Its flower spikelets are relatively small (7–10 mm long) and it does not produce stem seeds (i.e. cleistogenes).

Several other introduced grasses are relatively similar. These include serrated tussock (Nassella trichotoma), Mexican feathergrass (Nassella tenuissima), broad kernel espartillo (Amelichloa caudata), narrow kernel espartillo (Amelichloa brachychaeta), plumerillo (Jarava plumosa) and Uruguayan ricegrass (Piptochaetium montevidense). None of these species have collars (i.e. coronas) on their seeds. Differences between Lobed Needle Grass and similar species are illustrated by CRC (2003) and Richardson et al. (2006). Differences in the four species of Nassella occurring in Victoria are described and illustrated by Faithfull & Gillespie (2004).

Why Is It A Weed?

What are its impacts?

Lobed Needle Grass is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, Lobed Needle Grass has the potential to seriously degrade Australia's ecosystems (CRC 2003). Lobed Needle Grass is closely related to Serrated Tussock (Nassella trichotoma), a Weed of National Significance that costs south-eastern Australia's grazing industries more than $40 million a year in control expenditure and lost production (CRC 2003).

Agriculture: Even in its native Argentina, where the relatively unpalatable serrated tussock (Nassella trichotoma) and Chilean Needle Grass (N. neesiana) are used as fodder, Lobed Needle Grass is regarded as a serious weed due to its invasiveness and competitiveness and lack of usefulness as fodder. It is drought tolerant and forms dense infestations. While cattle may be able to tolerate Lobed Needle Grass, it is a major problem for sheep because the sharp seeds can damage skins and carcasses and contaminate fleeces. As seen with the closely related Serrated Tussock and Chilean Needle Grass, infestations of Lobed Needle Grass would result in significant loss in livestock production (CRC 2003). Nassella charruana shares the unpalatability traits of N. trichotoma and also the injurious seeds of N. neesiana, and within its native range, this species is considered highly competitive, even displacing other Nassella species. For these reasons, N. charruana poses a significant threat to temperate rangelands, particularly those with high rainfall and soil fertility Humphries & Florentine (2021).

Native ecosystems: Lobed Needle Grass is a successful competitor with native grasses and is impacting on native grasslands and open woodlands. Lobed needle grass forms dense competitive infestations. In Victoria (only state with this weed) it has invaded open woodlands and native and introduced grasslands including grassland dominated by other Nassella species

How does it spread?

Lobed Needle Grass reproduces by seed. Although the exact amount of seed produced is not known, the closely related species serrated tussock (Nassella trichotoma) and Chilean needle grass (N. neesiana) can produce tens of thousands of seeds per plant per year. The seeds are very sharp, and readily attach themselves to clothing, fur and equipment. Seeds can also be spread when soil is moved. Major roadworks near the site of one infestation led to the spread of Lobed Needle Grass. Anecdotal evidence suggests that the seedheads are not carried by wind like serrated tussock (CRC 2003). It has very sharp seed that are easily spread by attaching to clothing, fur or machinery and be be transported large distances. 

Based on climate suitability, the potential distribution of Lobed Needle Grass in Australia has been estimated at 600 000 ha. It could expand its range in Victoria and spread into eastern New South Wales, the Australian Capital Territory, south-eastern South Australia, north-eastern Tasmania and possibly south-eastern Queensland and south-western Western Australia (CRC 2003; Faithfull & Gillespie 2004).

What is its history in Australia?

A few samples of Lobed Needle Grass were imported as a potential pasture species in 1945 as part of the Commonwealth Plant Introduction program (Cook & Dias 2006). It has been growing at Epping, Victoria for four decades or more (CRC 2003). It was first recorded as a potential weed problem in 1995 in Victoria.

How To Manage It?

Best practice management

As with all weed management, prevention is better and more cost-effective than control. All Nassella species are prohibited from entering Australia (CRC 2003). Small infestations of Lobed Needle Grass can be easily eradicated if they are detected early but ongoing monitoring is needed to prevent re-infestation. Because there are relatively few Lobed Needle Grass infestations and it can potentially be eradicated before it becomes established, any new outbreaks should be reported immediately to your state or territory weed management agency or local council. Do not try to control Lobed Needle Grass without their expert assistance. Control effort that is poorly performed or not followed up can actually help spread the weed and worsen the problem (CRC 2003).

Non-chemical control: Plants are chipped out. Plants with flowers or a seed heads are bagged and burnt. Plants with flower heads never be slashed or mown as any seeds could be spread by wind or water to other sites or transported on machinery to other sites. 

Chemical control: Foliar spray when actively growing can be effective. For further detail on control and management of Lobed Needle Grass see CRC (2003); DPI NSW (2019); Faithfull & Gillespie (2004); Woldendorp & Bomford (2004) and Cunningham & Brown (2006).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Lobed Needle Grass flowers mainly from mid-spring to early summer. Seed is formed and drops throughout summer and early autumn. Most vegetative plant growth and seed germination occur in autumn and winter, although some germination may occur year round under suitable conditions (CRC 2003).

[Growth Calendar in CRC PDF.]

Where Is It Found?

Which states and territories is it found?

VIC

What areas within states and territories is it found?

Lobed Needle Grass's known distribution in Australia is limited to a few small infestations on the northern outskirts of Melbourne, from Thomastown, Plenty Gorge Metropolitan Park and near Cooper Street in Epping, where it is thought to have been present for more than 40 years (CRC 2003; see also Woldendorp & Bomford 2004; Cunningham & Brown 2006) where it occupies approximately 20 hectares (Humphries & Florentine 2021).

Where does it originate?

Lobed Needle Grass is native to Uruguay, Argentina, Paraguay and south-eastern Brazil (Sainty & Associates 2002).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

ACT, VIC

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

YES

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

YES

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Nassella charruana

Other scientific names (synonyms)?

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

Does it have other known common name(s)?

Uruguay Needle Grass