Water hyacinths are aquatic plants, consisting of seven different species. Water hyacinths are well-established in different parts of the world and can grow up to 3 feet in height. They produce attractive bluish flowers. The dark green leaves are circular or elliptical in shape. The thick, fibrous root system exists underwater. The sight of a water hyacinth on a body of water is quite beautiful, resembling a meadow full of blue flowers.
Water hyacinths are mostly known for their ability to multiply and propagate speedily. This floating perennial is one of the fastest-growing plants known to mankind. Reproduction is primarily achieved by means of a stem-like growth called stolon, which produces new plants. It also produces seeds, which birds distribute. The seeds can remain dormant and viable for as long as thirty years.
Water hyacinths are very hardy and can grow in almost any condition. They are even known to grow in toxic waters. However, these resilient plants cannot survive harsh northern winters.
Many people regard the invasiveness of water hyacinths negatively because the plants can cover entire water surfaces and cause oxygen depletion. The oxygen depletion harms the fish population and the aquatic ecosystem. Furthermore, the dense cover these plants form on the water surface can entirely block the sunlight required for the survival of other aquatic plants.
Water hyacinths propagate so fast that they can block waterways and navigation through rivers and lakes. They can also disrupt the flow of water in canals that are used for agricultural purposes, thereby causing economic damage.
They also provide the perfect breeding ground for mosquitoes. Biological control by the introduction of certain weevils has been somewhat successful in controlling the spread of the water hyacinth. This is the most widely preferred method of controlling water hyacinths, as it also results in a reduced need for herbicides.
Water hyacinths have the ability to tolerate high levels of toxins and pollution. The roots of these plants absorb pollutants and toxic substances such as mercury and lead. The cultivation of this plant is very helpful in clearing up murky water. As a result, it is highly useful in the treatment of waste water and industrially-polluted water.
Water hyacinths are used as food in some parts of East Asia and also possess some medicinal value. Due to the large quantities available, these plants also provide an excellent source for producing biogas and are also used as feed for livestock.
In East Asia, farmers use dried plants as sources of fuel. They then use burnt residue or ash as fertilizer. Water hyacinths, therefore, have a significant role to play in cleaning up after industrial and mining activities, and also in creating fuel, ethanol and fertilizer, among other useful products.