FULL SCIENTIFIC NAME
Eichhornia crassipes (Mart.) Solms
FAMILY NAME COMMON
FAMILY SCIENTIFIC NAME
Leaves with inflated petiole
Cross-section of petiole
Synonyms: Eichhornia speciosa Kunth
Piaropus crassipes(Mart.) Raf.
Eichhornia crassipes is a free-floating aquatic perennial with feathery, pendant roots. The thick, waxy leaves are arranged in a rosette and can reach 0.9 m (3 ft.) above the surface of the water. The blades of the leaves are orbicular to kidney-shaped and measure 4-12 cm (1.5-4.75 in.) across. One of the most distinctive features of this plant are its greatly inflated petioles which allow it to float on the surface of the water. This plant flowers in mid-summer in more northern areas. The flowers are arranged in a panicle that can be 4-15 cm (1.5-5.9 in.) long. They are showy and usually lilac in color (though rarely they can be white). The uppermost tepal has a darker purple blotch with a yellow center. The flowers measure 5-7 cm (2-2.75 in.) in diameter. The fruit is a capsule with three cells that contains up to 450 ribbed seeds. Page References Bailey 199, Crow & Hellquist 312, Fernald 396, Gleason & Cronquist 821, Holmgren 779, Magee & Ahles 317. See reference section below for full citations.
Eichhornia crassipes most often reproduces vegetatively by stolons, which it can do at an extremely rapid rate. It can also reproduce sexually and disperse by seed. Long distance dispersal can occur when seeds or plant fragments are carried by water currents or when fragments attach to boats.
Eichhornia crassipes is native to the Amazon Basin. It has been reported from five continents and at least 50 countries. In the United States it has been reported from the southern states, north to Virginia and Missouri and west to Arizona, California and Hawaii. There is an unsubstantiated report of it from Long Island as well. This species is not yet known to persist in New England.
HISTORY OF INTRODUCTION IN NEW ENGLAND
Eichhornia crassipes has not yet been reported to be naturalized in New England. There is a report of it being introduced into New Orleans in 1884 at an exposition. It likely spread as a result of its being a popular water garden plant. Every year it is discovered in lakes and ponds in southern New England where it is not known to persist from one growing season to the next.
HABITATS IN NEW ENGLAND,Aquatic,Lake or Pond,Roadside,Yard or Garden
Although this plant has not yet been reported as naturalized in New England, it is found in lakes and ponds and occasionally in water-filled ditches along roadsides where it is introduced each year.
Eichhornia crassipes is considered to be one of the worst weeds in the world. Vegetative reproduction allows it to spread rapidly, with some populations reported to double in 6-18 days. The seeds of this plant are reported to remain viable up to 20 years. Florida spends millions of dollars a year controlling the spread of this weed. It can clog waterways, degrade water quality and eliminate the habitat of certain species of aquatic animals. One acre of this plant can weigh up to 200 tons. Though it does not seem to be able to overwinter in New England at this time, repeated introductions may provide an opportunity for naturalization.
Documentation required: Photograph of plant from wild occurances
Best time for documentation: Late spring to fall (before frost)
Integrated Taxonomic Information System
Taxonomic information about the species
General information and map
Center for Aquatic and Invasive Plants, University of Florida
Extensive information including description, photographs and control information
Global Invasive Species Database
Information about this plant worldwide
Additional images of water-hyacinth
Information on biocontrol of water-hyacinth
Washington State Department of Ecology
Descriptive and ecological information on this plant
Agami, M. and K.R. Reddy. 1990. Competition for space between Eichornia crassipes (Mart.) Solms and Pistia Stratiotes L. cultured in nutrient-enriched. Aquatic Botany 38, 195-208. Bailey, L. H. 1949. Manual of Cultivated Plants. Macmillan, New York. Center, T.D. and N.R. Spencer. 1981. The phenology and growth of water hyacinth (Eichhornia crassipes (Mart.) Solms) in a eutrophic north-central Florida lake. Aquatic Botany 10: 1-32. Charudattan, R. 1986. Integrated control of waterhyacinth (Eichornia crassipes) with a pathogen, insects, and herbicides. Weed Science 34 (Suppl. 1): 26-30. Crow, G.E. and C.B. Hellquist. 2000. Aquatic and Wetland Plants of Northeastern North America. Vol 1. University of Wisconsin Press, Madison. Das, R.R. 1969. A study of reproduction in Eichornia crassipes (Mart.) Solms. Tropical Ecology 10: 195-198. Fernald, M.L. 1950. Gray's Manual of Botany 8th edition. American Book Company, New York. Gleason, H.A. and A.C. Cronquist. 1991. Manual of Vascular Plants of the Northeastern United States and Adjacent Canada. 2nd ed. New York Botanical Garden, Bronx, New York. Hammer, R.L. 1996. Eichhornia crassipes, p.99. In Randall, J.M. and J. Marinelli. [eds.]. Invasive Plants: Weeds of the Global Garden. Brooklyn Botanic Garden Inc., New York. Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. New York Botanical Garden, Bronx, New York. Madsen, J.D. 1993. Growth and biomass allocation patterns during water-hyacinth mat development. Journal of Aquatic Plant Management 31: 134-137. Magee, D.W and H.E. Ahles. 1999. Flora of the Northeast. University of Massachusetts Press, Amherst. Masifwa W.F., T. Twongo and P. Denny. 2001. The impact of water hyacinth, Eichhornia crassipes (Mart) Solms on the abundance and diversity of aquatic macroinvertebrates along the shores of northern Lake Victoria, Uganda. Hydrobiologica 452 (1-3): 79-88. Penfound, W.T. and T.T. Earle. 1948. The biology of the water hyacinth. Ecological Monographs. 18:449-72. Thomas, L. and L. Anderson. 1984. Waterhyacinth control in California. Aquatics 6: 11-16. USDA, NRCS. 2001. The PLANTS Database, Version 3.1. (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.