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WEED ALERT (PDF)
Download a page (PDF 169 KB) from Identification and Biology of Nonnative Plants in Florida’s Natural Areas – Second Edition, by K.A. Langeland, H.M. Cherry, et al. University of Florida-IFAS Pub SP 257. 2008.
This species is on the FL DACS Prohibited Aquatic Plant List – 5B-64.011. According to Florida Statute 369.25, “No person shall import, transport, cultivate, collect,
sell, or possess any noxious aquatic plant listed on the prohibited aquatic plant list established by the department without a permit issued by the department.”
See 5B-64.011 for more information.
Date of introduction to Florida: 1884 (ornamental, agriculture)
(from Strangers in Paradise, Impact and Management of Nonindigenous Species in Florida, Chapter 2: Florida’s Invasion by Nonindigenous Plants: History, Screening, and
Regulation, by D.R. Gordon and K.P. Thomas, pp. 21-37. Island Press, Washington, DC, 1997.)
EICHHORNIA CRASSIPES (Mart.) Solms
water hyacinth, jacinthe d'eau
pronounced: iek-horn-ee-a kras-i-pays
from: Eichhorn: Johann Albrecht Friedrich Eichhorn (1779-1856), Prussian minister of
education and public welfare, court advisor and politician
crass (L.): thick
plant with thick leaf stalks
Eichhornia speciosa Kunth
Piaropus crassipes (Mart.) Britton
hyacinth is a floating plant. This invasive nuisance is planta non grata in much of the world where it often jams rivers and lakes with uncounted thousands of tons of
floating plant matter. A healthy acre of water hyacinths can weigh up to 200 tons! In the U.S., water hyacinth is present throughout the southeast, as well as
in California and Washington state. In Florida, where for 100 years this weed had the upper-hand in water management, the water hyacinth in most places is under "maintenance control":
field crews constantly working to keep the plant numbers at their lowest possible levels, in
exchange for the rivers and lakes remaining usable.
Eichhornia crassipes grows in all types of
vary in size from a few inches to over three feet tall. They have showy
lavender flowers. Their leaves are rounded and
leathery, attached to
spongy and sometimes inflated stalks. The plant has dark feathery roots. Water hyacinth may be confused with
frog's-bit, Limnobium spongia.
- water hyacinth is a floating, flowering perennial
- floating, "obligate" (requiring a wet habitat)
- linked plants form dense rafts in the water and mud
- will halt boat traffic on rivers; will cover a lake surface from shore to shore
- an aquatic weed worldwide; in lakes, rivers, ponds, ditches of temperate climates
- temperature tolerance: water hyacinth is not winter-hardy; its minimum growth temperature
12o C (54o F); its optimum growth temperature is
25-30o C (77-86o F); its maximum growth temperature is
33-35o C (92-95o F) (Kasselmann 1995)
Eichhornia crassipes(Mart.) Solms
- monocot, perennial
- free-floating, except when stranded in the mud; mother plants and
daughter plants attached by floating stolons
- leaves formed in rosettes rise to three feet
above the water; leaves entire, ovate, rounded, circular, or broadly elliptic, to 6 in. wide; thick,
glossy, waxy green, waterproof; sides gently incurved and often undulate; leaf base hearshaped,
squared or rounded; veins dense, numerous, fine, longitudinal
- petioles (leaf stems) floating, creeping;
inflated, bulbous, spongy, to 12 in. long
- multiple (8 to 15) flowers in a single very
showy, spike (spathe) to 12 in. long; spike at top of erect thick stalk to 20 in. long, rising above
the leaves; each flower in the flower-spike with six lavender-blue petals (perianths), petal tips
slightly 2-lipped; uppermost petal somewhat larger, lavender, having a bright yellow,
blue-bordered central oval splotch; stamens 6, stigmas 3
- roots hanging submersed beneath floating
leaves, dark purplish to black, feathery, tips with long root caps
- fruit a capsule, 3-celled, with many seeds; seeds ribbed, formed in
submerged, withered flower; fruit and seeds are rarely observed; seeds may produce many
seedlings in moderate climates
- Eichhornia crassipes is native to Brazil
- there are about seven species of Eichhornia native to South America; among
them are E. azurea, E. diversifolius and E. paniculata
Distribution in the U.S.:
- Water hyacinth is present in the states of the southeast U.S., and
California, Hawaii, and the Virgin Islands. The occurrences in Arizona, Arkansas and
Washington, shown in the map above left, are now believed to be "eradicated".
- According to the U.S.G.S., water hyacinth has been reported in New York, Kentucky,
Tennessee and Missouri "where plants escape summertime cultivation but do not persist through
the winter...it is annually stocked in farm fish ponds in southern Arizona and southern
Delaware," but has not become established in the natural systems of these states.
How it got here:
- Eichhornia crassipes, water hyacinth, is believed to have been
introduced into the U.S. in 1884 at an exposition in New Orleans; within 70 years of reaching
Florida, the plant covered 126,000 acres of waterways (Schmitz et al. 1993)
- Eichhornia crassipes continues to be sold through aquarium supply dealers and over
Potential to spread elsewhere in U.S.:
- water hyacinth is found globally in the tropics and subtropics, but its spread is
limited by severe cold (Holm et al. 1977); its leaves regrow after moderate freezes
- water hyacinth grows faster than any other tested plant (Wolverton & McDonald 1979);
populations can double in as little as 6 days (Mitchell 1976)
- water hyacinth reproduces vegetatively and sexually; new rosettes (daughter plants) are
formed on floating stolons which grow from the mother plants; seedlings are produced in mild
climates (Penfound & Earle 1948)
- Eichhornia crassipes mats clog waterways, making boating, fishing and almost all other water activities, impossible
- water flow through water hyacinth mats is greatly diminshed
- an acre of water hyacinth can weigh more than 200 tons; infestations can be many, many
acres in size; mats may double their size in as little as 6-18 days (Mitchell 1976);
- water hyacinth mats degrade water quality by blocking the air-water interface and greatly
reducing oxygen levels in the water, eliminating underwater animals such as fish (Penfound &
- water hyacinth greatly reduces biological diversity: mats eliminate native submersed plants
by blocking sunlight, alter emersed plant communities by pushing away and crushing them, and also
alter animal communities by blocking access to the water and/or eliminating plants the animals
depend on for shelter and nesting (Gowanloch 1944)
- in Florida, millions of dollars a year used to be spent on water hyacinth control; finally getting
the plant under "maintenance control" has greatly reduced that expenditure
Control - Due to decades of university, state and federal research and experience with Eichhornia crassipes in the U.S., several methods have been developed to help in its management:
- the action of mechanical harvestors and chopping machines remove water
hyacinth from the water and transport it to disposal on shore; chopping
machines grind the plant into bits and spray the slurry across the water
- years of research to find insect
biocontrols has resulted in the successful introduction of two water hyacinth
weevils, which are believed to be keeping water hyacinth under maintenance control in many
places; however biocontrol fish which are able to control submersed plants are
ineffective against the floating water hyacinth
- registered aquatic herbicides do provide temporary control of water hyacinth
See: http://edis.ifas.ufl.edu/ag262 Efficacy of Herbicide Active Ingredients Against Aquatic Weeds
What can you do?
- First, clean your boat before you leave the ramp! Transporting
plant fragments on boats, trailers, and in livewells is the main introduction route to new lakes and
- But, there's plenty more you can do to help.
Laws and lists:
- is "state-listed" in Arizona, Florida, Puerto Rico and South Carolina
- is on the Florida Prohibited Plants list, Florida Department of Environmental
- is on the Florida Exotic Pest Plant Council list: Category I - "plants invading and disrupting native plant communities in Florida"
Want to know more?
The information contained on this web page was extracted from published
scientific literature and agency reports. It is important to know that plant research, like most
areas of scientific research, is still relatively young and incomplete--much may have been
published about the physiology of one plant but not about its management; much may have been
published about how to culture and grow another plant but not about its natural ecology.
Thousands of research articles may have been published about one invasive plant, but perhaps
only a dozen about another.
If you want to read the research yourself, perhaps to clarify or expand an area of information
contained here, or to help determine your own line of research, you are welcome to query the
world's largest collection of international scientific literature about aquatic, wetland and invasive
plants, the APIRS bibliographic database, which contains more than 69,000 citations and their content
keywords. Or you might want to ask us to do
it for you and e-mail the search results to you.
This is the literature about Eichhornia crassipes that was used to
develop this web page. More research items about this plant may be found at APIRS:
- Gowanloch JN. 1944. The econimc status of water-hyacinth in
Louisiana. La. Conserv. 2:3-8
- Holm LG, Plucknett DL, Pancho JV, Herberger JP. 1977. The
world's worst weeds: distribution and biology. Honolulu: University Press of Hawaii. 609 pp.
- Kasselmann C. 1995. Aquarienpflanzen. Egen Ulmer GMBH & Co.,
Stuttgart. 472 pp. (In German)
- McCann JA et al. 1996. Nonindigenous aquatic and selected terrestrial
species of Florida-Status, pathway, and time of introduction, present distribution, and significant
ecological and economic effects. Southeastern Biological Science Center, Gainesville, 256 pp.
- Mitchell DS. 1976. The growth and management of Eichhornia
crassipes and Salvinia spp. in their native environment and in alien sitautions. In: Varshney CK, Rzoska J, editors, Aquatic weeds in Southeast Asia. The Hague:
Dr. W. Junk b.v., Publishers. 396 pp.
- Penfound WT, Earle TT. 1948. The biology of the water hyacinth. Ecol.
- Schmitz DC, Schardt JD, Leslie AG, Dray FA, Osborne JA, Nelson BV. 1993. The ecological impact and management history of three invasive alien aquatic plants in
Florida. In: McKnight BN, editor, Biological pollution - the control and
impact of invasive exotic species. Indianapolis: Indiana Acad. Science. 261 pp.
- Simpson, D., Sanderson, H. 2002. Eichhornia crassipes. Curtis’s Bot. Mag. 19(1):28-34.
- Van TK, Steward KK. 1982. Evaluation of chemicals for aquatic plant
control. Annual Report 1981, Ft. Lauderdale, FL, 66 pp.
- Vandiver VV. 1999. Florida aquatic weed management guide. Univ. of
FL, IFAS, Cooperative Extension Service, Publ. SP-55, 130 pp.
- Wolverton BC, McDonald RC. 1979. Water hyacinth (Eichhornia
crassipes) productivity and harvesting studies. Econ. Botany 33:1-10.
Download the Recognition Card of Eichhornia crassipes (PDF 500 KB).
See more information about water hyacinth as contained in the
book, Identification & Biology of Non-Native Plants in Florida's Natural
Areas by K.A. Langeland and K. Burkes.
Here is an article on using water hyacinth to make things in
View the UF/IFAS Assessment, which lists plants according to their invasive status in Florida.
See the herbarium specimen image of the University of Florida Herbarium Digital Imaging Projects.
For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.
|| This web page was authored in June, 2001, by Victor Ramey (Center for Aquatic and Invasive Plants, University of Florida), with significant contribution from Barbara Peichel (Sea Grant, University of Minnesota). The information contained herein is based on the literature found in the APIRS database.