Water hyacinth-a pretty noxious weed

It was meant to be a beautiful ornamental aquatic plant, but turned into one the world’s worst water weeds.
Water hyacinth was introduced to Australia as an ornamental aquatic plant and released into ponds and lagoons in metropolitan Brisbane and public parks all over Queensland in the early 1900s. However, due to its rapid spread and extensive root system it soon became a major pest of rivers, creeks and dams, choking wetlands, killing wildlife and interfering with transport and  recreational use of the waterways. Today infestations are controlled by a combination of mechanical, biological and herbicide treatments.

The plant started to become a major problem in the Brisbane River in 1901 as it was swept downstream as far as the city reaches after flooding upstream. Infestations have continued periodically since then, as shown in these pictures near Kangaroo Point from the 1960s.
River hyacinth infestation on the river near Kangaroo Point ca. 1960. (State Library of Queensland. ID: 6668-0001-0010)  

Ferry trying to get through a water hyacinth infestation at Kangaroo Point in 1964. (National Library of Australia 1483961431-1)

The most effective control method is removal and eradication by herbicide. This news item is a call for action to remove the deadly weed as it makes  river navigation difficult and often impossible.