The feathery, freely hanging roots are purple-black. Water hyacinth is a free-floating perennial aquatic plant (or hydrophyte) native to tropical and subtropical South America. An erect stalk supports a single spike of 8–15 conspicuously attractive white flowers with six petals. They have long, spongy, bulbous stalks. The leaves are 10–20 cm (4–8 inches) across on a stem, which is floating by means of buoyant bulb-like nodules at its base above the water surface. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 m (3 ft) in height.