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Pampas grass (Cortaderia selloana)

Pampas grass is an introduced environmental weed recorded across several Australian states and territories. Dense infestations can displace native ground flora, hinder overstorey regeneration and create fire hazards.

Key facts

Type: Weed, grass.

Native to: South America: Brazil, Argentina, Uruguay and Chile.

Established in: QLD, NSW, ACT, VIC, TAS, SA, WA.

Other names: common pampas, common pampas grass, cut throat grass, silver pampas grass.

Identification

  • A large, long-lived tussock-forming grass, usually 2–4 m tall and sometimes reaching 6 m.
  • Its narrow leaves are 60–200 cm long, have very sharp, finely toothed edges, and droop towards the ground as they mature.
  • Large, feathery seed-heads are usually whitish, cream or silvery when young, measure 25–100 cm long and fade to light brown or straw-coloured.
  • Female flower florets have silky hairs; male florets are hairless.
  • Look-alike: Pink pampas grass (Cortaderia jubata) has young seed-heads usually pinkish or purplish, while those of pampas grass are usually whitish or silvery.
  • Look-alike: New Zealand pampas grass (Cortaderia richardii) has relatively sparse seed-heads and distinct secondary leaf veins.

Where it grows

In Australia it grows in temperate, subtropical and occasionally semi-arid regions, especially damp places such as wetlands, swamps and stream banks, as well as disturbed sites, bushland, grasslands and roadsides.

Why it matters

  • Dense infestations can exclude most native ground flora and seriously impede recruitment of overstorey species.
  • It invades wetlands, stream banks and mangrove-swamp margins, as well as drier coastal forests, heathlands, open woodlands and grasslands.
  • Large amounts of flammable material and dense tufts of dead leaves can create a fire hazard.
  • Sharp leaf edges can cut skin, and wind-blown pollen may exacerbate asthma and hay fever.

How it spreads

  • It reproduces mainly by seed, which can form through fertilisation or apomixis.
  • Seeds are normally dispersed by wind and may also spread by water, machinery or dumped garden waste.

Control options

  • Consult the New South Wales Department of Primary Industries Agfact on pampas grasses, the Tamar Valley Weed Strategy information page, or the Environmental Weeds Action Network information page for management guidance.
  • Check local requirements before managing plants: New South Wales Class 4 declarations require control according to measures in a local control authority management plan in covered areas.
  • In Tasmania, measures to reduce, eradicate or restrict the species may be required; check applicable state and local requirements before undertaking management.

Hygiene and washdown

  • Seeds may be spread by machinery, so take care when moving machinery through or away from infested areas.
  • Avoid spreading dumped garden waste containing pampas grass.
  • 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): No national listing. Managed under state and territory law.
  • 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: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Permitted, not declared. Listed as a permitted organism in WA, so it can be brought in, but it is not a declared pest.
  • 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, 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.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • 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
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development

Sources