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Japanese Knotweed

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Japanese knotweed
Japanese knotweed, foliage - Photo by Jack Ranney; University of Tennessee
Scientific Name: 
Fallopia japonica (Houtt.) Ronse Decr. (ITIS)
Synonym: 
Polygonum cuspidatum Siebold & Zucc.; Reynoutria japonica Houtt.
Common Name: 
Japanese knotweed, fleeceflower, Mexican bamboo, huzhang
Native To: 
Asia (Stone 2010)
Date of U.S. Introduction: 
Late 1800s (Stone 2010)
Means of Introduction: 
Introduced as an ornamental (Stone 2010)
Impact: 
Crowds out native species (Stone 2010)

Spotlights

USDA. Animal and Plant Health Inspection Service.

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) has issued the final environmental assessment (EA) for releasing Japanese knotweed psyllid (Aphalara itadori) to manage Japanese, giant, and bohemian knotweeds (Fallopia japonica, F. sachalinensis, and their hybrid, F. x bohemica). After careful analysis, APHIS has determined that releasing Japanese knotweed psyllid within the continental United States is not likely to have a significant impact on the environment. Based on this determination, APHIS will not prepare an environmental impact statement and will begin issuing permits for the release of Japanese knotweed psyllid.

Distribution / Maps / Survey Status

University of Georgia. Center for Invasive Species and Ecosystem Health.
Provides state, county, point and GIS data. Maps can be downloaded and shared.

Images

University of Georgia. Center for Invasive Species and Ecosystem Health.

Videos

Google. YouTube; University Nebraska - Lincoln. Extension.

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Japanese Knotweed.

Council or Task Force
Ohio Invasive Plants Council.
See also: Invasive Plants of Ohio for worst invasive plant species identified in Ohio's natural areas

Washington State Recreation and Conservation Office. Washington Invasive Species Council.

Partnership
University of Alaska - Anchorage. Alaska Center for Conservation Science.
See also: Non-Native Plant Species List for additional factsheets (species biographies) and species risk assessment reports of non-native species present in Alaska and also non-native species currently not recorded in Alaska (potential invasives)
IUCN. Species Survival Commission. Invasive Species Specialist Group.

Ontario's Invading Species Awareness Program (Canada).

University of Georgia. Center for Invasive Species and Ecosystem Health.
CABI Bioscience.

New York Invasive Species Clearinghouse.

Great Britain Non-Native Species Secretariat.

Centre for Invasive Species Solutions; Atlas of Living Australia; Australian Government. Department of Agriculture, Water and the Environment.

Federal Government
USDA. FS. Rocky Mountain Research Station. Fire Sciences Laboratory.
Smithsonian Institution. Smithsonian Environmental Research Center. Marine Invasions Research Lab.
USDA. NRCS. National Plant Data Center.

USDA. ARS. National Genetic Resources Program. GRIN-Global.

International Government

Cornwall County Council (United Kingdom).

State and Local Government
New Hampshire Department of Agriculture, Markets, and Food. Division of Plant Industry.
See also: New Hampshire's Prohibited Invasive Plant Fact Sheets for additional invasive trees, shrubs, vines, and herbaceous plants
Michigan Department of Natural Resource; Michigan State University Extension. Michigan Natural Features Inventory.
See also: Best Control Practice Guides for more guides

Indiana Department of Natural Resources. Invasive Plant Species Assessment Working Group.

See also: Species Assessments and Invasive Species for exotic animal and plant pests invading Indiana, causing economic and visual damage

Washington State Noxious Weed Control Board.
California Department of Food and Agriculture.
See also: Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources
Missouri Department of Conservation.

Pennsylvania Department of Conservation and Natural Resources.

See also: Invasive Plant Fact Sheets for plant species (trees, shrubs, vines, herbs and aquatic plants) that have impacted the state's natural lands

Wisconsin Department of Natural Resources.

King County Department of Natural Resources (Washington). Water and Land Resources Division.

Colorado Department of Agriculture. Conservation Services Division. Noxious Weed Program.

Academic
Pennsylvania State University. Pennsylvania Sea Grant.
See also: Aquatic Invasive Species: Resources for additional species information

Pennsylvania State University. Cooperative Extension.

Columbia University. Center for Environmental Research and Conservation.
North Carolina State University. Cooperative Extension. Going Native: Urban Landscaping for Wildlife with Native Plants.
University of Maine Cooperative Extension.
See also: Maine Invasive Plants & Entire Series for entire series of 22 fact sheets and invasive plants brochure (available in HTML/PDF or for purchase)
Ohio State University. Ohio Agricultural Research and Development Center.

Citations