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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. See the Noxious Weeds Program for more information.
    USDA. APHIS. Plant Protection and Quarantine.



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.


Federal Noxious Weed Disseminules of the U.S. - Fact Sheet: Hydrilla verticillata
USDA. APHIS. PPQ. Center for Plant Health Science and Technology; California Department of Food and Agriculture.

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).

EncycloWeedia: Data Sheet - Hydrilla, Egeria, and Elodea
California Department of Food and Agriculture.
Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources.

Colorado Department of Agriculture. Noxious Weed Management Program.

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

Invasive Plants in Pennsylvania: Hydrilla (PDF | 114 KB)
Pennsylvania Department of Conservation and Natural Resources.

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

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.

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.


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: Oct 01, 2015
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