- Native to South America, Water hyacinth was introduced to Australia as an aquatic ornamental. It has a high growth rate and can quickly form thick mats on the water surface of static or slow flowing fresh water such as dams, streams, lagoons, and drains.
- Reproduces by seed, but mainly through the vegetative production of daughter plants on stolons.
- An erect or horizontal free-floating, occasionally rooted in shallow water, perennial water weed to 60 cm high.
- Fibrous, feather-like root system, trailing freely in the water and growing up to 1 m long.
- Dark-green, smooth, fleshy leaves in a rosette on bulbous stems.
- Flowers are bluish-purple with 6 petals, the upper one with a yellow blotch in the centre carried in spikes about 15 cm long on stalks arising from the middle of rosettes.
- Fruit is narrow 3-celled capsule about 1 to 1.5 cm long, containing up to 300 seeds.