Invasive weed found in Harrisdale waterway

Following the discovery of an invasive aquatic weed in Harrisdale, the City of Armadale is calling for residents to help manage the spread of Amazon frogbit.

The Amazon frogbit can affect the biodiversity of waterways and was spotted in the Balannup Drain recently.

Originating from Central and South America the weed spreads rapidly via fragmentation of the parent plant. It reproduces prolifically through both seed and vegetative division.

One single leaf can grow roots and begin reproducing vegetatively. Each plant can produce multiple seed pods with each pod containing up to 30 seeds that are viable for at least three years.

Mayor Henry Zelones OAM, JP said the plant is commonly used in aquariums and ponds. However, when disposed of inappropriately, it can congest drains, waterways and wetlands.

“It has the potential to completely choke our waterways as it can form into a dense mat of up to 2500 plants per square metre.

“Early detection and containment is essential to manage this invasive weed before it affects our native vegetation, water quality and habitat for native wildlife.”

Multiple outbreaks have occurred around the Perth Metropolitan Area since the initial discovery in the Liege Street Wetlands in Canning in 2013. Each infestation is thought to be a result of residents inappropriately disposing of their aquarium plants into the stormwater network or local waterways. 

“Prevention and early detection is important to managing the Amazon frogbit and the City is currently monitoring the infestation discovered in the Balannup drain.

“To prevent the invasive weed travelling further downstream, booms have been installed in the Balannup drainage system,” said Mayor Zelones.

Anyone who sees this invasive weed should contact the City’s Bushcare Supervisor with photos and location at [email protected].

For more information on the weed, visit www.sercul.org.au/our-projects/weed-management.