The water-hyacinth (Eichhornia crassipes) [ike horn' ee a kras' i pays] is the beauty and the beast plant. Native to Brazil, it was introduced to the U.S. in New Orleans around 1884. The plant may have been introduced to Florida by cattlemen looking for a fast growing source of fodder. Cows did not care for the plant. Consequently, in seventy years of unchecked growth, the plants covered 126,000 acres of lakes and waterways.

The water-hyacinth floats; the inflated petioles of the leaves are filled with aerenchyma, air-chambered buoyant tissue. The blackish purple roots can grow 24 to 30 inches (60 cm. to 75 cm.) The plant reproduces both vegetatively through stolons and sexually (seed). During optimum weather and in water polluted by fertilizer or sewage, the number of plants doubles every 6 days.

The water-hyacinth is excellent for cleaning up polluted water. One or two plants in a fish pond remove ammonia and clear an algae bloom within days. But the plants can degrade the water by reducing the oxygen content, suffocating the fish. Unfortunately, fish pond owners often dump excess plants into natural water bodies instead of the compost bin. Water-hyacinths are on the U.S. federal noxious weeds list and are illegal to own or transport in Florida.

The beautiful water-hyacinth spells disaster for a water body. The long roots preclude most fish from using the area under the plants. The thick growth chokes out emergent vegetation and shades out submergent plants. Oxygen content drops increasing eutrophication, the process where a water body changes into a marsh because of the buildup of organic matter.

In Africa, water-hyacinths have become established in Lake Victoria. The plants clog the intakes of hydroelectric dams, strand boats and tangle propellers, and have become thick enough to damage docks and concrete quays. One acre of water-hyacinths weighs over 200 tons. It is estimated that it will cost $5.5 million (US) to remove the plants from Lake Victoria.

Of all things, the plant was named in honor of a Prussian politician, court advisor, and minister of education and public welfare, Johann Albrecht Friedrich Eichhorn.