Water Hyacinth
Eichhornia crassipes
Center for Aquatic Plants
|
Water HyacinthEichhornia crassipes |
| University of Florida, IFAS, Center for Aquatic Plants |
Invasive Nonindigenous Plants in Florida |
is
one of the worst weeds in the world--aquatic or terrestrial. Until only a few years ago, this
floating plant was a major problem in Florida (as it still is in many places throughout the world)
covering as many as 125,000 acres of water: boat traffic on several rivers was halted; hundreds of
lakes and ponds were covered from shore to shore with up to 200
tons of hyacinths per acre!
Water hyacinth (Eichhornia crassipes)
This South American native was introduced into Florida in the 1880s. Its growth rate is among the highest of any plant known: hyacinth populations can double in as little as 12 days. Besides blocking boat traffic and preventing swimming and fishing, water hyacinth infestations also prevent sunlight and oxygen from getting into the water. Decaying plant matter also reduces oxygen in the water. Thus, water hyacinth infestations reduce fisheries, shade out submersed plants, crowd out emersed plants, and reduce biological diversity.
Now, however, water hyacinth in Florida is under "maintenance control",
thanks to years of concerted effort by local, state and federal water managers. Maintenance
control means that plant managers have the plants at a low level, and keep them at a low level
using herbicides, machines and biocontrol insects.
If only a year passed without constant vigilance by the couple of hundred aquatics management
agencies in the state, water hyacinths likely would return to infestation levels that would require
millions of dollars worth of effort to return to maintenance levels.
How To Identify Water Hyacinth
Water hyacinth is a free-floating plant, which
grows up to three feet in height. It has thick, waxy, rounded, glossy leaves, which rise well above the water surface on
stalks. The leaves are broadly ovate to circular, 4 to 8 inches in diameter, with gently incurved
sides, often undulate. Leaf veins are dense, numerous, fine and longitudinal. Water hyacinth leaf stalks are bulbous and spongy. Water hyacinth
grows an erect thick stalk (to 20 inches long) at the top of which is a single spike of several (8 to
15) showy flowers. The flowers have 6 petals,
purplish blue or lavender to pinkish, the upper petals with yellow, blue-bordered central
splotches.
Water hyacinth reproduces vegetatively by short runner
stems (stolons) that radiate from the base of the plant to form daughter plants, and
also reproduces by seed. Its roots are purplish black and feathery.
Water hyacinth may be confused with frog's-bit (Limnobium spongia). Compare the two species.
For more information and pictures about water hyacinth, as contained in the
Langeland/Burks book, Identification & Biology of Non-Native Plants in Florida's Natural
Areas, download this Acrobat .PDF file.
