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Yellow burrhead (Limnocharis flava)

Yellow burrhead is an aquatic weed that can outcompete native plants, restrict water flow and build up silt in waterways. It has naturalised in northern Queensland, where eradication programs are in place, and has potential to invade northern NSW; cultivated plants were found and seized in the NSW South East in 2026.

Key facts

Type: Weed, aquatic.

Native to: Central America.

Established in: QLD, NT.

Other names: limnocharis, yellow velvet leaf, sawah lettuce, sawah flower rush.

Identification

  • It is an erect plant anchored in mud or sediment and can grow up to 1 m above the water surface.
  • Its pale-green, velvety leaves have 11–15 parallel veins and can reach 30 cm long and 25 cm wide.
  • Triangular, fleshy leaf stalks can reach 85 cm long and produce milky sap when broken.
  • Pale-yellow, cup-shaped flowers have three petals, are 2–4 cm wide and grow in clusters of 2–15.
  • Its round green capsules turn brown as they mature and split into 12–18 crescent-shaped segments.

Where it grows

In Australia it grows in shallow water in streams, freshwater swamps, wetlands, ditches and along riverbanks, and can also grow beside water in humid environments.

Why it matters

  • It outcompetes native aquatic plants and reduces food and habitat for fish and other aquatic animals.
  • It can cause silt to build up, narrowing waterways, and can slow or block water flow in natural waterways, agricultural channels and drains.
  • Dense growth can restrict access to water for people and animals and create habitat for mosquitoes.

How it spreads

  • Most seeds spread by water: mature fruit floats downstream, then seeds sink when released; seeds can remain viable for at least four years.
  • A plant can produce up to a million seeds per year; capsules contain an average of 1,000 seeds and may contain up to 1,500.
  • Seeds can travel in contaminated mud on vehicles, machinery, footwear and animals, especially water birds; plantlets can also form when a flowering stem bends into mud, takes root, or breaks off and floats away.

Control options

  • Do not attempt to treat or dispose of yellow burrhead yourself.
  • If you see it anywhere in NSW, report it immediately by calling the NSW Biosecurity Helpline on 1800 680 244.
  • NSW DPIRD Agriculture and Biosecurity will lead the initial response for treatment and disposal; contact your local council weeds officer for identification advice.

Hygiene and washdown

  • Avoid moving contaminated mud on vehicles, machinery or footwear, as it can carry seeds.
  • Take care not to transport plant material or contaminated mud between waterways.
  • 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 weed eradication program. Targeted for eradication under the nationally cost-shared National Tropical Weeds Eradication Program. Report any sighting straight away.
  • Queensland: Restricted matter, categories 2, 3, 4, 5. Report it to Biosecurity Queensland within 24 hours; do not give it away, sell or release it into the environment; do not move it; do not keep it. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Prohibited matter. It is an offence to deal with it, and you must notify NSW DPIRD as soon as you become aware of it.
  • 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: 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: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Declared weed, Class C. Class C: must not be introduced to the NT.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

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)
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources