Water hyacinth (Eichhornia crassipes) is a perennial floating weed that forms dense mats, reducing water quality and impeding water flow.
- erect plant, to 600mm
- dark green rounded leaves to 300mm in diameter held upright by swollen stems
- leaf stalk is thick and spongy, with bladder-like swellings
- bluish-purple or lilac-coloured flowers, 50-80mm in diameter with a yellow centre carried in dense spikes projecting to 600mm above the plant.
Why is it a problem?
- blocks sunlight and air exchange from the water
- can cause up to four times the loss of water from normal water surface evaporation due to high rates of transpiration through the leaves
- rotting plants remove oxygen from the water causing pollution, stagnation and death of fish, crustaceans and other aquatic organisms
- large mats create breeding sites for mosquitoes
- large infestations can restrict water flow in irrigation channels and interfere with irrigation equipment
- reduces the amenity value of aquatic areas by preventing swimming and boating.
- no current reported outbreaks in SA
- current infestations in NSW and QLD.
- reproduces by seed and above ground shoots, most common in lagoons and pools
- flowering occurs from October throughout the summer months
- flower remains open for several days before withering and releasing seeds into the water after 18 days.
How it spreads
- major method of spread is through human activity such as boating or fishing.