The water hyacinth is a plant that is an invasive species, gaining the reputation as one of the worst of the aquatic invasive species. Originally found only in tropical portions of South America, water hyacinth has populated much of the waterways in many states in the U.S. Water hyacinth produces a beautiful flower but this does not compensate for the problems the plant can cause for the environment and for those who desire to utilize the waterways it clogs for recreational purposes.
The water hyacinth floats freely on the surface of the water. It possesses shiny leaves, dark green in color, which has a rounded shape or are elliptical. The leaves are as wide as 6 inches and waterproof, rising as tall as 3 feet above the surface of the water. The roots of the plant hang down from beneath the leaves and have a fine feathery appearance, growing in great numbers. The flowers emerge on a foot tall spike and are quite attractive, with six lavender petals, one with a yellowish patch inside.
The plant has established itself in the Deep South, especially in states such as Florida. It is also in Hawaii, the Virgin Islands, California and Washington State. Water hyacinth has become a worldwide problem, showing up and taking over rivers and lakes in Asian and African nations as well as India, New Zealand and Australia. Luckily, the plant does not do well in cold weather, which has kept it from advancing into northern states.
The State of Washington's Department of Ecology website states that one seemingly harmless event precipitated the invasion of water hyacinth in the United States. During an exposition held in Louisiana in the years 1884 and 1885, an individual visiting from Florida purchased some water hyacinths at the event and brought them back to his home state. Apparently, he released them into the wild, in the St. John's River system, with the result being these plants began to spread, resulting in the problems that these ecosystems face today.
The plant grows do densely that according to the Center for Aquatic and Invasive Plants website, one single acre of water hyacinths has a weight of 200 tons. The thick mats the plant forms overwhelm a river or lake and make such activities as boating and fishing impossible. The amount of vegetation also serves to decrease water flow, causes water to become oxygen depleted and provides mosquitoes with a breeding ground. Water hyacinth will crowd out native plant species, which in turn alters entire ecosystems as plants that animals depend on will not thrive, throwing the biome out of whack.
Control of water hyacinth is a costly process and involves a number of methods. One is to harvest the plants, but this requires great labor and is a constant battle as the plant is so prolific it is difficult with which to keep up. Herbicides work well but can also kill native plant species. Two kinds of weevils and a certain species of moth can affect the amount of water hyacinth in an area, prompting some states to introduce these insects into areas plagued by the weed.