Keep an eye out for highly invasive water hyacinth

19 February 2026

Victorians are urged to keep an eye out for water hyacinth after an infestation on a rural property in Anakie, north of Geelong.

Water hyacinth (Eichhornia crassipes) is a State prohibited weed (SPW) declared under the Catchment and Land Protection Act 1994.

Agriculture Victoria Leading Biosecurity Officer Incursion Control Kaitlin Wright said it’s considered the world’s worst water weed and has infested rivers, dams, lakes and irrigation channels on every continent except Antarctica.

‘Thriving in warm weather, water hyacinth is a floating water plant that can reproduce by daughter plants or seed. They can be identified by their swollen stems with air-filled tissue for buoyancy and large mauve-coloured flowers.’

Ms Wright said while the weeds may look attractive, their ability to quickly choke waterways harms native plants and wildlife.

‘When you consider that one water hyacinth plant can produce more than 3,000 seeds over summer, you see how easily they can take over a backyard pond.’

She said water hyacinth can have a range of impacts on properties, including:

• smothering water bodies by blocking access for stock, clogging infrastructure and irrigation equipment
• reducing water quality by reducing dissolved oxygen and sunlight, and increasing organic matter
• pushing out native species and creating additional habitat for undesirable pests such as mosquitoes
• extremely quick growth, with infestations rapidly growing in short time spans
• high treatment costs due to the fast regrowth and large seedbank.

A report made by the owners of the property alerted Agriculture Victoria to the infestation, which is approximately 5,000 m² and is impacting an agricultural business. Its origin is currently unknown, but it is most commonly spread by unsuspecting gardeners.

Agriculture Victoria is working closely with the property owners to treat the site and remove the infestation.

Ms Wright said Victorian residents or visitors are encouraged to keep an eye out for a vibrant green floating plant with a stalk of many pale purple flowers with a distinctive yellow spot surrounded by a darker purple patch on the uppermost petal.

City of Greater Geelong Executive Director City Infrastructure Amanda Locke said, ‘We are working with Agriculture Victoria to raise community awareness and we encourage our rural communities to keep an eye out for this fast‑spreading weed in dams and waterways and report sightings to help stop its spread’.

If you suspect you have water hyacinth on your property, please take a photo of the plant and email it to weed.spotters@agriculture.vic.gov.au, or call the Customer Contact Centre on 136 186.

You can also make a report on the Report a State prohibited weed page.

More information on water hyacinth is available on the Agriculture Victoria website.

Media contact: media@deeca.vic.gov.au