Yellow burrhead (Limnocharis flava)

Also known as: limnocharis, yellow velvet leaf, sawah lettuce, sawah flower rush

Yellow burrhead is a water weed with yellow cup-shaped flowers. It can block water channels and outcompete native plants.

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How does this weed affect you?

Yellow burrhead invades lakes, rivers, dams, wetlands and irrigation channels. Once established, it can:

• cause silt to build up 
• alter or block water flow in channels and drains
• outcompete other aquatic plants
• reduce shelter and food for fish and other aquatic animals
• create habitat for mosquitos.

What does it look like?

Yellow burrhead is an erect plant anchored in mud or sediment. It can grow up to 1 m above the water surface. In year-round wet conditions, it behaves as a perennial. In seasonally dry areas it grows as an annual.

Leaves are:

• pale green
• 5–30 cm long and 4–25 cm wide
• velvety with 11–15 parallel veins
• narrow when young
• broader and more oval-shaped as they age
• on triangular, fleshy stalks up to 75 cm long that produce milky sap when broken.

Flowers are:

• pale yellow with three petals
• cup-shaped
• 2-4 cm wide
• in clusters of 2–15 on triangular stalks
• present year-round.

Fruit are

• round capsules
• green, turning brown as they mature
• up to 2 cm wide
• made up of 12–18 crescent-shaped segments (each containing up to 115 seeds), which separate when ripe.

Seeds are:

• dark brown
• 1.5 mm long
• horseshoe-shaped with obvious ridges.

Where is it found?

There are no known infestations of yellow burrhead in NSW but it has the potential to invade northern NSW. Eradication programs are in place for infestations in northern Queensland.

Yellow burrhead is native to Central America. It has naturalised in the USA, South America, India and south-east Asia. It is a major weed in Malaysia, Sri Lanka and Indonesia where it invades wetlands, rice fields and irrigation channels. 

Unusual foliage and attractive yellow flowers make yellow burrhead an appealing pond plant. Although prohibited, it may have entered the country as a garden ornamental.

Maps and records

• Recorded presence of Yellow burrhead during property inspections (Map: Biosecurity Information System - Weeds, 2017-2023)
  These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.
  
  

How does it spread?

By seed

Plants can produce mature fruit in as little as 46 days. Each capsule contains over 1000 seeds and seeds can remain viable for at least 4 years. Plants can produce up to a million seeds per year.  

Most seeds are spread by water. Mature fruit falls off the plant and floats downstream and the seeds sink when released from the fruit. Seeds can also be spread in contaminated mud stuck to vehicles, machinery, footwear and animals, especially water birds.

By plant parts

New plantlets grow after the flowering stem loses all its flowers and bends over into the mud. The end of the stem takes root in the mud and develops a new plant or it can break off and float away to form a new infestation.

References

Abhilash, P. C., Singh, N., Sylas, V. P., Kumar, B. A., Mathew, J. C., Satheesh, R., & Thomas, A. P. (2008). Eco-distribution mapping of invasive weed Limnocharis flava (L.) Buchenau using geographical information system: implications for containment and integrated weed management for ecosystem conservation. Taiwania, 53(1), 30-41.

Brooks, S. J., Panetta, F. D., & Galway, K. E. (2008). Progress towards the eradication of mikania vine (Mikania micrantha) and limnocharis (Limnocharis flava)in northern Australia. Invasive Plant Science and Management, 1(3), 296-303.

Hosking JR, Sainty GR, Jacobs SWL & Dellow LL (in prep) The Australian WeedBOOK

Nayar, B. K., & Sworupanandan, K. (1978). Morphology of the fruit and mechanism of seed dispersal of the freshwater weed Limnocharis flava. In Proceedings of the Indian Academy of Sciences-Section B (Vol. 87, No. 2, pp. 49-53). Springer India.

Queensland Government. (2020). Restricted invasive plant: Limnocharis flava. Retrieved 24 September 2020 from: https://www.daf.qld.gov.au/__data/assets/pdf_file/0017/125432/limnocharis.pdf

More information

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Control

Please do not attempt to treat or dispose of this weed yourself. Report this plant if you see it anywhere in NSW by calling the helpline listed at the top of this page immediately. 

NSW DPI will lead an initial response for the treatment and disposal of the plant to stop it from spreading.

Herbicide options

See Using herbicides for more information.

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PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Only products registered for aquatic use)
Rate: Up to 200 mL in 10 L of water
Comments: Spot spray application
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area	Duty
All of NSW	General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
All of NSW	Prohibited Matter A person who deals with prohibited matter or a carrier of prohibited matter is guilty of an offence. A person who becomes aware of or suspects the presence of prohibited matter must immediately notify the Department of Primary Industries

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Reviewed 2020