Photographer: Wendy VanDyk Evans Affiliation: Bugwood-USA Source: www.bugwood.org Copyright: CC BY NC 3.0 US
Roots are dark and feathery, only extending into the soil during flowering. Plants float on and extend above the water due to enlarged-bulb-like petioles. Leaves are thick, shiny, bright green, 1-5 inches in width, and are kidney-shaped, or slightly concave. Flowers are conspicuous and lavender, in groups of 8-15 atop a stalk reaching 16 inches. Flowers are 6-petaled, the central lobe of which has a yellow oval-shaped spot. While rarely observed, fruit is a 3-celled capsule, containing many seeds, found in a submerged, withered flower.
Alters native vegetation and fish communities by lowering light penetration and dissolved oxygen levels. Impedes boat traffic on rivers and waterways and clogs irrigation canals and intake pumps.
Primarily reproduces vegetatively, via fragmentation and offshoots of the branching stems. It will also reproduce via seed production in favorable conditions (high temperature and high humidity). Peak flowering occurs in late summer and early fall.
Water hyacinth is thought to be native to the Amazon River basin of South America. It was introduced to the United States in 1884 at the Cotton States Exposition in New Orleans, Louisiana. It spread across the southeastern U. S. and was identified in Florida in 1895. It was reported to be in California in 1904.
Native Origin: South America (Germplasm Resources Information Network); NatureServe Explorer, Bugwood.org
Water hyacinth will grow in a wide variety of aquatic habitats including lakes, ponds, rivers, wetlands and marshes. It will grow most prolifically in water of high nutrient content; it has been used in wastewater treatment facilities. It can withstand drastic fluctuations in water level, flow rates, acidity and low nutrient levels. These characteristics make it a popular plant for residential water gardens.
U.S. Present: AL, AZ, CA, CO, CT, DE, FL, GA, HI, IL, IN, KS, KY, LA, MA, MD, MN, MO, MS, NC, NJ, NY, OR, PR, RI, SC, TN, TX, VA, VI, WA, WI
It resembles the invasive Anchored Water Hyacinth (Eichhornia azurea).
In Florida, Eichhornia crassipes may be confused with the floating form of a somewhat similar appearing native aquatic plant, frog's bit (Limnobium spongia). The presence of small, white flowers and petioles that are not bulbous or inflated aid in distinguishing the native plant from water hyacinth.
Alternatives: Pontederia cordata (pickerelweed), Utricularia gibba (humped bladderwort), Nymphaea odorata (American white waterlily), N. mexicana (yellow waterlily).
Avoid introducing this plant to local waterways. 2,4-D and glyphosate herbicides are only effective on small populations. Plant harvesting machines/choppers or complete drainage is necessary for large infestations. Care should be taken to control nutrient inputs from the surrounding watershed.
USE PESTICIDES WISELY: Always read the entire pesticide label carefully, follow all mixing and application instructions and wear all recommended personal protective gear and clothing.
Contributions from Texas Invasives for this species page are greatly appreciated.
Germplasm Resources Information Network); NatureServe Explorer, Bugwood.org
Mitchell D.S. 1976. The growth and management of Eichhornia crassipes and Salvinia spp. In their native environment and in alien situations. In: Varshney C.K. amd J. Rzoska (Eds.). Aquatic weeds in Southeast Asia. W. Junk Publishers, Netherlands. 396 p.
Room P.M. and I.V.S. Fernando. 1992. Weed invasions countered by biological control: Salvinia molesta and Eichhornia crassipes in Sri Lanka, Aquatic Botany 42:99-107.
Schmitz D.C., Schardt J.D., Leslie A.J., Dray F.A., Osbourne J.A. and B.V. Nelson. 1993. The ecological impact and management history of three invasive alien aquatic plant species in Florida. In: McKnight (Ed.). Biological pollution-The control and impact of invasive exotic species. Indiana Academy of Science, Indianapolis. 261 p.
Villamagna, A. M., & Murphy, B. R. 2010. Ecological and socio‐economic impacts of invasive water hyacinth (Eichhornia crassipes): a review. Freshwater biology, 55(2), 282-298.