Water hyacinth is a floating plant with round to oval leaves up to 10 inches in diameter, although smaller leaves are common. Leaves are bright green and shiny and held upright so they act like sails, which facilitates distribution of the plant. The leaf stalk is spongy and thick and helps to keep the plant bouyant. A mass of fine roots hang in the water column. They are blue-ish purple or lilac colored with a yellow spot.
Water hyacinth can form impenetrable mats of floating vegetation.
Water hyacinth has not been found in the wild in Washington but it is sold as an ornamental plant in garden stores in the state. Although it is thought that water hyacinth cannot survive Washington's winters, its presence as an ornamental makes it possible for escape and growth in the wild under the right conditions. Water hyacinth reproduces by seeds and vegetatively. Daughter plants form on rhizomes forming dense beds of water hyacinth. In one study, two plants produced 1200 daughter plants in four months.