Alligator weed - an aquatic weed present in Australian backyards

Lalith Gunasekera, Keith Turnbull Research Institute, Department of Natural Resources and Environment, PO Box 48, Frankston, Victoria 3199, Australia.


Alligator weed, Alternanthera philoxeroides is considered to be one of the worst aquatic weeds in the world. The aquatic form of the plant has the potential to become a serious threat to waterways, agriculture and the environment. The terrestrial form grows into a dense mat with a massive underground rhizomatous root system. The canopy can smother most other herbaceous plant species. Alligator weed was recently discovered being mistakenly grown as the leafy vegetable Mukunu-wenna or sessile joyweed (Alternanthera sessilis), a popular leafy vegetable in Sri Lanka, in all Australian states.

In Victoria, an information campaign has been conducted to educate the public about the impact and identification of A. philoxeroides. This was followed by an eradication campaign conducted with the co-operation of the Sri Lankan community. The supply of alternative plants is crucial to the success of the eradication campaign. Two forms of the Australian native species A. denticulata (lesser joyweed), one with larger leaves and one with smaller leaves, are accepted by the Sri Lankan community as alternative herbal species. The larger leaf form is more popular and is easy to grow.


Plant Protection Quarterly (1999) 14 (2) 77-78.