common water hyacinth
Eichhornia crassipes (Mart.) Solms

Overview

Appearance

Eichhornia crassipes is a free floating aquatic plant that has invaded aquatic areas throughout the eastern and southern portions of the United States. Plants can grow to 3 ft. (1 m) in height.

Foliage

The leaves are oval to elliptical, thick, up to 6 in. (15 cm) wide and waxy with spongy petioles. Leaves curve inward at the edges.

Flowers

The very showy blue-purple flowers are born on upright spikes. Each flower has six petals with the uppermost having a yellow patch.

Fruit

This plant reproduces chiefly by vegetative means.

Ecological Threat

Eichhornia crassipes invades lakes, ponds, rivers, marshes, and other types of wetland habitats. It can quickly form dense floating mats of vegetation (populations can double in size in two weeks!). These dense mats restrict light to the underwater environment, reduce the light availability for submersed plants and aquatic invertebrates, and deplete the oxygen levels. Eichhornia crassipes is native to South America and was first introduced as an ornamental into the United States in 1884 at the Cotton States Exposition in New Orleans.

Resources

• Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service
• Southeast Exotic Pest Plant Council Invasive Plant Manual - SE-EPPC
• Element Stewardship Abstract - The Nature Conservancy
• Global Invasive Species Database - Invasive Species Specialist Group

Selected Images

Maps

Invasive Listing Sources

• Alabama Invasive Plant Council
• Alabama Noxious Weeds - Class C Noxious Weed
• Alachua County Cogongrass Initiative
• Apalachicola Invasive Working Group
• Arizona Noxious Weeds
• Arkansas Noxious Weeds - Noxious/Prohibited
• California Invasive Plant Council
• Connecticut Invasive Plant List
• Connecticut Invasive Plant Working Group
• Florida Exotic Pest Plant Council - Category I
• Florida Noxious Weeds
• Georgia Exotic Pest Plant Council - Category 1
• Idaho Noxious Weeds
• Invasive Species of Concern in Georgia
• John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
• Kentucky Exotic Pest Plant Council
• Maryland Aquatic Nuisance Species Plan
• Maryland Department of Natural Resources Policy: Restriction on Planting Exotic Invasive Plants
• Maryland Invasive Species Council - Invasive Species of Concern in Maryland
• Michigan’s Invasive Species Watch List
• Mid-Atlantic Field Guide to Aquatic Invasive Species
• Minnesota DNR invasive species list
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• National Park Service, National Capital Region Exotic Plant Management Team Invasive Plant List
• Native Plant Society of Oregon, 2008
• New Hampshire Invasive Plant Species Watch List
• New Jersey Invasive Species Strike Team 2017 Invasive Species List
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• Ontario’s Invading Species Awareness Program Tracked Species List
• Rhode Island Natural History Survey
• South Carolina Illegal Aquatic Plants
• Texas Noxious Weeds
• Virginia Invasive Plant Species List
• WeedUS - Database of Plants Invading Natural Areas in the United States
• Wisconsin Noxious Weeds
• Wisconsin's Invasive species rule – NR 40

References