In response to the threat of aquatic weeds to the Murray Darling Basin (MDB), a 2014 pilot project investigated potential aquatic weed risks and spread pathways via water delivery initiatives. Five weeds were the focus of the project; sagittaria, water hyacinth, alligator weed, cabomba and Mexican water lily, as these were determined to be high priority threats in risk assessments (Champion et al. 2008), and have potential to spread from their current infestations in the MDB. The links below provide identification resources and distribution information for these five high-risk weeds.

There are, however, more than five aquatic weeds that pose a risk to the MDB and other aquatic areas. The lead agency in your state can provide more information on these and other significant weeds.


New South Wales: Department of Primary Industries
Victoria: Department of Environment, Land, Water and Planning
South Australia: Biosecurity SA

5 High Priority Aquatic weeds in the MDB


Alligator weed (Alternanthera philoxeroides Mart.)

Alligator weed
Distribution of Alligator weed in the MDB
NSW WeedWise





Mexican water lily (Nymphaea mexicana Zucc.) 

Mexican water lily, also known as Yellow water lily
Distribution of Mexican water lily in the MDB
NSW WeedWise
Yellow water lily factsheet (GM Water)




water hyacinth

Water hyacinth (Eichhornia crassipes (Mart.) Solms)

Water hyacinth
Distribution of Water hyacinth in the MDB
NSW WeedWise


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