Biosecurity Spotters logo

Lobed needle grass (Nassella charruana)

Lobed Needle Grass is an invasive, unpalatable tussock grass that can form dense infestations and exclude more desirable plants. In Australia it is currently restricted to a few small infestations near Melbourne, but it could spread further if not managed.

Key facts

Type: Weed, grass.

Native to: Uruguay, Argentina, Paraguay and south-eastern Brazil.

Established in: VIC.

Other names: Uruguay Needle Grass.

Best time to act: Flowering is mainly from mid-spring to early summer, and foliar spraying can be effective when plants are actively growing; seed forms and drops through summer and early autumn.

Identification

  • This tufted, short-rhizomatous perennial spear grass grows to about 1 m high.
  • Its rough leaves are narrow and rolled inwards, growing from the base and reaching up to 60 cm long and 2 mm wide.
  • Shiny, branching flower heads can grow to 30 cm long.
  • The sharp seeds have an awn 4.5–9 cm long and a long corona; two pale brown to white lobes sit at the top of the dark brown lemma.
  • Look-alike: It can resemble native Austrostipa and Poa grasses and other Nassella species, which also have sharp seeds with long curved or bent awns.
  • Look-alike: Lobed Needle Grass is distinguished by the two pale lobes at the top of the lemma and its long corona, about 3.5–5 mm long.

Where it grows

In Australia it is known from a few small infestations on Melbourne’s northern outskirts, including Thomastown, Plenty Gorge Metropolitan Park and near Cooper Street in Epping.

Why it matters

  • Dense infestations compete with native grasses and other plants, affecting native grasslands and open woodlands.
  • The grass is unpalatable and competitive, and is regarded as a serious weed even within its native range.
  • Sharp seeds can damage sheep skins and carcasses and contaminate fleeces.
  • It poses a significant threat to temperate rangelands, particularly those with high rainfall and fertile soils.

How it spreads

  • It reproduces by seed, and the sharp seeds readily attach to clothing, fur and equipment.
  • Seeds can also spread when soil is moved, and machinery can transport them between sites.

Control options

  • Report new outbreaks promptly to the state or territory weed management agency or local council, and do not attempt control without expert assistance.
  • Plants can be chipped out; plants with flowers or seed heads should be bagged and burnt.
  • Never slash or mow plants with flower heads, as this can spread seeds.
  • Foliar spraying when plants are actively growing can be effective; use registered herbicides and follow approved methods.

Hygiene and washdown

  • Check and clean clothing, fur, equipment and machinery to remove attached seeds.
  • Avoid moving soil from infested sites, as this can spread seed.
  • Inspect and clean vehicles, plant and footwear before leaving an infested area, paying attention to tyres, radiators, belly plates, tracks and floor mats.
  • Wash down at a designated bay where runoff is contained and can be monitored for seedlings.
  • Record each washdown so the client has evidence of clean entry and exit.

Classification by state

  • Australia (national): National Environmental Alert List. One of 28 weeds named on the National Environmental Alert List as early-stage invaders with serious potential to harm the environment.
  • Queensland: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Not a priority weed. Not a state or regional priority weed in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: State prohibited weed. State prohibited weeds are the highest priority: the Victorian Government is responsible for eradicating them, so report any sighting to Agriculture Victoria.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • Tasmania: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • Northern Territory: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • Australian Capital Territory: Declared pest, notifiable, prohibited. It is a declared pest throughout the ACT. You must report it to ACT Biosecurity. Dealing with it, such as selling, moving or keeping it, is prohibited.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria

Sources