common water hyacinth Eichhorniacrassipes (Mart.) Solms
Appearance
Eichhornia crassipes is a free floating aquatic plant that has invaded aquatic areas throughout the eastern and southern portions of the United States. Plants can grow to 3 ft. (1 m) in height.
Foliage
The leaves are oval to elliptical, thick, up to 6 in. (15 cm) wide and waxy with spongy petioles. Leaves curve inward at the edges.
Flowers
The very showy blue-purple flowers are born on upright spikes. Each flower has six petals with the uppermost having a yellow patch.
Fruit
This plant reproduces chiefly by vegetative means.
Ecological Threat
Eichhornia crassipes invades lakes, ponds, rivers, marshes, and other types of wetland habitats. It can quickly form dense floating mats of vegetation (populations can double in size in two weeks!). These dense mats restrict light to the underwater environment, reduce the light availability for submersed plants and aquatic invertebrates, and deplete the oxygen levels. Eichhornia crassipes is native to South America and was first introduced as an ornamental into the United States in 1884 at the Cotton States Exposition in New Orleans.