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You are here: Home / Aquatic Species / Species Profiles / Hydrilla
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HydrillaScientific name: Hydrilla verticillata (L. f.) Royle (ITIS)

Common names: Hydrilla, Florida elodea, water thyme, Indian star-vine

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Selected Resources

Native To: Eastern Hemisphere; U.S. strains possibly originated in Asia (Balciunas et al. 2002)

Date of U.S. Introduction: 1950s (Masterson 2007)

Means of Introduction: Aquarium trade (Masterson 2007)

Impacts: Crowds out native species; impedes irrigation and boating (Balciunas et al. 2002)

Current U.S. Distribution:

Federally Regulated:

  • Listed as a Federal Noxious Weed under the Plant Protection Act, which makes it illegal in the U.S. to import or transport between States without a permit (USDA, APHIS - Noxious Weeds Program)



Selected Resources:


Aquatic Nuisance Species Task Force.

Invasive Plants of California's Wildlands - Hydrilla verticillata
California Invasive Plant Council.
Bossard, C.C., J.M. Randall, and M.C. Hoshovsky (Editors). 2000. Invasive Plants of California's Wildlands. University of California Press. Berkeley, CA

Southeast Exotic Pest Plant Council Invasive Plant Manual - Hydrilla
Southeast Exotic Pest Plant Council.


Invasive Plant Atlas of New England (IPANE) - Hydrilla
University of Georgia. Center for Invasive Species and Ecosystem Health.

Invasive Plant Atlas of the United States - Hydrilla
University of Georgia. Center for Invasive Species and Ecosystem Health.

Fact Sheet: Hydrilla
Massachusetts Introduced Pests Outreach Project.

New York Invasive Species Information - Hydrilla
New York Invasive Species Clearinghouse.

Northeast Aquatic Nuisance Species Panel.

Texas Invasives Database - Hydrilla verticillata

Invasive Species Compendium - Hydrilla verticillata
CAB International.

Global Invasive Species Database - Hydrilla verticillata (aquatic plant)
World Conservation Union. Invasive Species Specialist Group.


Hydrilla - Aquatic Plant Information System (APIS)
DOD. USACE. Engineer Research and Development Center. Environmental Laboratory.

Germplasm Resources Information Network (GRIN) - Hydrilla verticillata
USDA. ARS. National Genetic Resources Program.

Hydrilla - Biological Control of Invasive Plants in the Eastern United States (Aug 2002)
Published by: USDA. Forest Service. Publication FHTET-2002-04.

PLANTS Database - Hydrilla
USDA. NRCS. National Plant Data Center.

Indian River Lagoon Species Inventory - Hydrilla verticillata
Smithsonian Institution. Smithsonian Marine Station at Fort Pierce.

Hydrilla verticillata - Plant Pest Control (PDF | 58 KB)
Hawke's Bay Regional Council (New Zealand).

Hydrilla, Egeria, and Elodea - EncycloWeedia
California Department of Food and Agriculture.

Colorado Department of Agriculture. Noxious Weed Management Program.

Hydrilla - Weed Alert (PDF | 739 KB)
Florida Fish and Wildlife Conservation Commission.

Hydrilla - Vermont Invasive Exotic Plant Fact Sheet (PDF | 89 KB)
Vermont Agency of Natural Resources. Environmental Conservation.

Hydrilla - Invasive Alien Plant Species of Virginia (PDF | 117 KB)
Virginia Department of Conservation and Recreation. Natural Heritage Program; Virginia Native Plant Society.

Hydrilla - Non-Native Freshwater Plants
Washington State Department of Ecology. Water Quality Program.

Class A Noxious Weed: Hydrilla
Washington State Noxious Weed Control Board.


Hydrilla - Invasive Plant Species of Alaska (PDF | 113 KB)
University of Alaska - Anchorage. Alaska Natural Heritage Program.

Hydrilla - Nonindigenous Aquatic and Selected Terrestrial Species of Florida
University of Florida. Center for Aquatic and Invasive Plants.

Aquatic Invaders: Hydrilla - Aquatic Invader Toolkit (PDF | 673 KB)
Illinois-Indiana Sea Grant.

Hydrilla verticillata - Maine Invasive Plants Bulletin no. 2527
University of Maine. Cooperative Extension.

Invasive Plant Atlas of the MidSouth - Hydrilla
Mississippi State University. GeoResources Institute.

Managing Hydrilla (PDF | 122 KB)
University of Nevada - Reno. Cooperative Extension.

Hydrilla (PDF | 86 KB)
University of Pennsylvania. Morris Arboretum.


Colorado Weed Management Association.

Hydrilla - Maine's Interactive Field Guide to Aquatic Invaders and Their Native Look Alikes
Maine Volunteer Lake Monitoring Program. Maine Center for Invasive Aquatic Plants.

Hydrilla verticillata
Pacific Island Ecosystems at Risk.

Hydrilla - Practical Guidebook to the Control of Invasive and Aquatic Wetland Plants of the San Francisco Bay-Delta Region
San Francisco Estuary Institute.


Balciunas, J.K., M. J. Grodowitz, A.F. Cofrancesco and J.F. Shearer. 2002. Hydrilla. In: Biological Control of Invasive Plants in the Eastern United States. United States Department of Agriculture Forest Service. Forest Health Technology Enterprise Team. Morgantown, West Virginia. FHTET-2002-04.

Integrated Taxonomic Information System. Hydrilla verticillata. [Accessed Sep 10, 2014].

Masterson, J. 2007. Hydrilla verticillata. In: Indian River Lagoon Species Inventory. Smithsonian Marine Station.

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Last Modified: Mar 20, 2015
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