The water hyacinth (Eichhornia crassipes) is an attractive lavender-flowered floating plant considered an invasive nuisance in the world's fresh waterways. It jams rivers and lakes with floating matter that can weigh up to 200 tons per acre, according to the University of Florida Extension. The water hyacinth was introduced to the United States from Brazil in 1884, and its adaptations have caused it to rapidly spread throughout the southeastern states as well as California, Washington state, Hawaii and the Virgin Islands.
One reason the water hyacinth has taken hold so strongly is its rapid growth habit. According to the University of Florida Extension, its populations can double in six days, making its growth faster than any other tested plant. Once introduced to fresh water, this perennial reproduces rapidly and can cover an acre in one growing season.
The water hyacinth reproduces both vegetatively and sexually in all types of fresh water. The new plants, called rosettes, are formed on the floating stolons of the mother plant. As the plant grows into ever-enlarging, thick mats, water flow is diminished, boating and fishing become impossible, and the waterway's biodiversity is greatly reduced, according to the University of Florida Extension.
The water hyacinth was introduced to the United States at an exposition in New Orleans. Its ornamental qualities, including 2- to 3-inch lavender flowers, rounded, leathery leaves and thick, spongy stalks, quickly landed it on the shelves of nurseries. Homeowners purchased it for their ornamental ponds, and it made its way into fresh waterways. The State of Washington Department of Ecology recommends disposing of ornamental water hyacinth in compost heaps and keeping it away from fresh waterways.