Alligatorweed

Scientific name: Alternanthera philoxeroides (Mart.) Griseb.

Synonym: Achyranthes philoxeroides

Common names: Alligatorweed, alligator weed, pig weed

Native To: South America

Date of U.S. Introduction: First reported in Alabama in 1897

Images: Invasive.org and Google

Means of Introduction: Probably introduced through ballast water

Impact: Forms dense mats that crowd out native species and impede recreational activities such as boating, swimming, and fishing

Current U.S. Distribution: Southeastern U.S., Califorinia

• PLANTS Database Map (see complete PLANTS Profile for county distribution and native status)
• Early Detection & Distribution Mapping System

U.S. States and U.S. National Parks Where Reported Invasive: WeedUS Database map

Management Plans: Aquatic Species

Selected Internet Resources:

• Federal Government
• State Government
• University/Academic
• International
• Organizations

Federal Government

Alternanthera philoxeroides (Mart.) Griseb.
Integrated Taxonomic Information System.
Taxonomy

Alternanthera philoxeroides (Mart.) Griseb. (Alligatorweed) - Noxious and Nuisance Plant Management Information System (PMIS)
United States Army Corps of Engineers. Engineer Research and Development Center. Environmental Laboratory.
Identification/Description; Photographs; Impacts; Distribution

Alternanthera philoxeroides Article Citation Search - AGRICOLA Database
USDA. National Agricultural Library.
Research; Special Note: NAL Catalog Search (resources)

Alternanthera philoxeroides - Germplasm Resources Information Network (GRIN)
USDA. ARS. National Genetic Resources Program.
Taxonomy; Legal Aspects

Alligatorweed - Biological Control of Invasive Plants in the Eastern United States
USDA. Forest Service.
Taxonomy; Identification/Description; Photographs; Impacts; Life Cycle; Habitat; Distribution; Controls; Legal Aspects

Plant Profile for Alternanthera philoxeroides - PLANTS Database
USDA. NRCS. National Plant Data Center.
Taxonomy; Photographs; Distribution; Legal Aspects

Alternanthera philoxeroides - Indian River Lagoon Species Inventory
Smithsonian Institution. Smithsonian Marine Station at Fort Pierce.
Taxonomy; Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Distribution

State Government

Alligatorweed - EncycloWeedia
California Department of Food and Agriculture.
Identification/Description; Photographs; Life Cycle; Habitat; Distribution; Dispersion; Controls

Alligator Weed
South Carolina Department of Natural Resources. Freshwater Fisheries Section.
Identification/Description; Illustrations; Habitat; Dispersion; Controls

Alligatorweed - Invasive Alien Plant Species of Virginia (PDF | 224 KB)
Virginia Department of Conservation and Recreation. Natural Heritage Program and Virginia Native Plant Society.
Identification/Description; Illustrations; Impacts; Habitat; Distribution

University/Academic

Alligator weed
University of Florida. IFAS. Center for Aquatic and Invasive Plants.
Identification/Description; Photographs; Habitat; Distribution

Alligatorweed - WeedUS Database
University of Georgia. Center for Invasive Species and Ecosystem Health.
Taxonomy; Identification/Description; Photographs; Illustrations; Introduction History; Impacts

Alligatorweed - Georgia Lawn Weed Control Fact Sheet (Aug 1999; PDF | 24 KB)
University of Georgia Cooperative Extension. Camden County Extension Service.
Identification/Description; Photographs; Habitat; Controls

Alligator Weed
Mississippi State University Extension Service; Mississippi Agricultural and Forestry Experiment Station.
Identification/Description; Illustrations; Introduction History; Controls

Alligatorweed - Aquatic Weed Fact Sheet (PDF | 173 KB)
North Carolina State University. College of Agriculture and Life Sciences.
Identification/Description; Photographs; Introduction History; Impacts; Habitat; Distribution; Dispersion

Alligatorweed - Biological Control of Weeds in Texas
Texas A&M University. Department of Entomology.
Identification/Description; Photographs; Impacts; Habitat; Controls

Alligator Weed - Aquaplant
Texas A&M University. Texas Agricultural Extension Service.
Identification/Description; Photographs; Illustrations; Controls

Alligatorweed - Virginia Tech Weed Identification Guide
Virginia Polytechnic Institute and State University. Department of Forestry.
Identification/Description; Photographs

International

Fact Sheet: Alligator weed (Sep 2007; PDF | 235 KB)
Biosecurity Queensland (Australia).
Identification/Description; Photographs; Illustrations; Impacts; Life Cycle; Habitat; Distribution; Controls; Legal Aspects

Alligator Weed - Weed Management Guide (2003; PDF | 353 KB)
Cooperative Research Centre for Australian Weed Management.
Identification/Description; Photographs; Impacts; Life Cycle; Habitat; Distribution; Dispersion; Controls; Special Note: See also Alligator Weed Strategic Plan (PDF | 720 KB)

Alligator weed
Environment Bay of Plenty Regional Council (New Zealand).
Taxonomy; Identification/Description; Photographs; Impacts; Habitat; Dispersion; Controls; Legal Aspects

Alternanthera philoxeroides - Weeds in Australia
Department of the Environment, Water, Heritage and the Arts (Australia).
Identification/Descrption; Photographs; Introduction History; Impacts; Habitat; Distribution; Dispersion; Controls

Alternanthera philoxeroides (Amaranthaceae)
European and Mediterranean Plant Protection Organization.
Identification/Description; Photographs; Impacts; Habitat; Distribution; Controls

Alligator Weed (Jan 2004; PDF | 458 KB)
Hunter and Central Coast Regional Environmental Management Strategy (Australia). Weed Management Program.
Identifcation/Description; Photographs; Impacts; Dispersion; Controls; Legal Aspects

Alternanthera philoxeroides (aquatic plant, herb) - ISSG Global Invasive Species Database
World Conservation Union. Invasive Species Specialist Group.
Taxonomy; Identification/Description; Photographs; Impacts; Habitat; Distribution; Dispersion; Controls

Organizations

Alligatorweed - Plant Fact Sheet
Aquatic Plant Management Society.
Identification/Description; Photographs; Habitat; Distribution

Alligatorweed - Galveston Bay Invasive Species Risk Assessment (PDF | 122 KB)
Galveston Bay Estuary Program.
Identification/Description; Impacts; Life Cycle; Habitat; Distribution; Controls

Alligatorweed, pig weed
Guide to Invasive Plants of the Galveston Bay Area.
Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Distribution; Controls

Alternanthera philoxeroides
Pacific Island Ecosystems at Risk.
Identification/Description; Photographs; Habitat; Distribution; Controls

Alternanthera philoxeroides
TexasInvasives.org.
Taxonomy; Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Distribution; Controls; Legal Aspects