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Serrated tussock (Nassella trichotoma)

A tussock grass with almost no feed value that takes over temperate pasture and native grassland, with seed heads that break off and roll long distances in the wind.

Key facts

Type: Weed, grass.

Native to: South America.

Established in: NSW, ACT, VIC, TAS.

Identification

  • Dense, fine-leaved tussock to 50 cm tall, with tightly rolled leaves that feel rough when rubbed downwards.
  • Purple-tinged, open, drooping seed heads in spring.
  • White, unbranched leaf bases that are tightly packed.
  • Look-alike: Native tussock grasses (Poa spp.) have smoother leaves; confirm identification before treating.

Where it grows

Temperate pasture, native grassland and roadsides on the tablelands and in Victoria and Tasmania.

Why it matters

  • Pasture productivity loss, as stock will not eat it.
  • Displaces native grassland.

How it spreads

  • Wind-blown seed heads.
  • Seed in hay, on vehicles and on livestock.

Control options

  • Chip out or spot spray isolated plants.
  • Registered herbicides with pasture improvement to provide competition.
  • Map and prevent seed set each year.

Hygiene and washdown

  • Slash clean areas first, and clean equipment before leaving infested paddocks.
  • 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): Weed of National Significance. One of 32 nationally agreed priority weeds, managed through national strategies with all states and territories.
  • Queensland: Prohibited matter. Report it to Biosecurity Queensland on 13 25 23 within 24 hours and do not move or deal with it. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Sale prohibited; Regional priority in 8 of 11 regions. It must not be imported into NSW or sold anywhere in the state. Regional priority weed in Central Tablelands, Central West, Greater Sydney, Hunter, Murray, North West, Northern Tablelands, Riverina. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Regionally controlled / regionally prohibited weed (varies by region). Where it is regionally prohibited, landowners must take all reasonable steps to eradicate it on their land. Where it is regionally controlled, landowners must take all reasonable steps to prevent its growth and spread on their land.
  • South Australia: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • Western Australia: Declared pest (C1), prohibited. C1 Exclusion: to be kept out of WA, or out of the parts of WA where it is not established. Report any sighting to DPIRD. It must not be brought into WA (prohibited organism).
  • Tasmania: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • Northern Territory: Check NT list. There is no NT weed profile for it. Check the NT declared weeds list for its current status.
  • Australian Capital Territory: Declared pest, prohibited. It is a declared pest throughout the ACT. 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.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Australian Capital Territory: Biosecurity Act 2023 (ACT), administered by ACT Biosecurity
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania

Sources