Practical information to identify and manage non-native, invasive plants
The Quiet Invasion:A Guide to Invasive Plants of the Galveston Bay Area
Eichhornia crassipes
| USDA Symbol: | EICR |
| ITIS TSN: | 42623 |
| Presence: | Current Invaders |
| Habitat: | Aquatic |
| Native Range: | South America |
Toxic Characteristics
This species is not known to be toxic.Geographic Distribution
Naturalized populations exist in Texas and all other Gulf Coast states, in addition to many other states. Found in all counties of the Lower Galveston Bay watershed.Introduction Pathways
Introduced in 1884 at a New Orleans expo. Continues to spread via the aquarium plant trade and by boat traffic which fragment and disperse plant parts in waterways.Specific Primary Habitats
Thrives in slow-moving, nutrient-enriched (nitrogen, phosphorus, potassium) freshwater. Found in small wetlands, ditches, shallow lakes, slow-moving rivers and canals. Does not tolerate salinity or temperatures below 55 F.Identifying Characteristics
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.Reproduction Characteristics
Primarily reproduces vegetatively, via fragmentation and offshoots of the branching stems. Will also reproduce via seed production in favorable conditions (high temperature and high humidity). Peak flowering occurs in late summer and early fall.Growth Characteristics
The plant first develops high root biomass, followed by above-water biomass and daughter plant production. Mats can double in size in 6-18 days and an acre-size mat can weigh more than 200 tons.Ecological, Economic, or Social Impact
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.Suggested Control Methods
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.|
Native Species Alternatives
Below is a list of alternative plants that are native to the area:
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Lists
This species belongs to the following lists:
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Images
To view a larger version of an image, click on the thumbnail. Mat of infestation of the common water hyacinth in a wetland. Photo courtesy of Willey Durden, USDA Agricultural Research Service, www.forestryimages.org; Image Number 0002100. |
 Aerial view of the common water hyacinth. Photo courtesy of Gerald J. Lenhard, www.forestryimages.org; Image Number 0014017. |
 Close-up of a flower of the common water hyacinth. Photo courtesy of Josh Hillman, FloridaNature.org, www.forestryimages.org; Image Number 1237096. |
 The beginnings of a common water hyacinth invasion. Photo courtesy of John D. Byrd, Mississippi State University, www.forestryimages.org; Image Number 1391151. |
 Infestation of the common water hyacinth while in flower. Photo courtesy of David R. Worley, Florida Department of Environmental Protection, www.forestryimages.org; Image Number 1624034. |
 Common water hyacinth at the Wallisville Lake Project near the Trinity River. Photo courtesy of Lisa Gonzalez. |
 Common water hyacinth overtaking open water of the Wallisville Lake Project near the Trinity River. Photo courtesy of Lisa Gonzalez. |