Native to Latin America, and thought to have been introduced to the United States as an ornamental plant. Now present throughout the milder climates of the U.S., from Florida to California, where it can be a severe problem in navigable waterways and irrigation canals, where its thick, smothering growth obstructs movement and water flow.
A floating perennial weed that usually reproduces vegetatively from stolons growing off the parent plant. New plants easily separate with disturbance or physical damage. Reproduction may also be from seeds that fall to the bottom of the aquatic habitat, and may remain there in a dormant state through dry periods, germinating once water is available again.
Water hyacinth tends to grow mat-like, eventually covering the water completely over very large areas.
Mature plants can grow as tall as 2 feet, with the large leaves on long, fleshy stalks, and the flower heads growing out from the leaves to a length of 14 inches. Plants are floating, but may also have roots extending into the mud below. Root systems are fibrous and with many branches.
Leaves are of two types – submerged leaves are long and narrow while aerial leaves are broad and round. Leaves are fleshy and shiny green, and arise from the base of the plant in a circular pattern. The stalks of the aerial leaves are swollen as air cells.
Flower stalks are over 1 foot long with a single leaf clasping the stalk. Each stalk has a cluster of around 8 large, violet flowers in a compact terminal grouping.
Characteristicts Important to Control:
Physical disturbance may spread the plants by vegetative growth. Seeds can remain dormant for long periods. Physical removal is possible if thorough.