Japanese Knotweed

Scientific name: Fallopia japonica (Houtt.) Ronse Decr.

Synonym: Polygonum cuspidatum Siebold & Zucc.

Common names: Japanese knotweed, fleeceflower, Mexican bamboo, huzhang

Native To: Asia

Date of U.S. Introduction: Late 1800s

Images: Invasive.org and Google

Videos: Japanese Knotweed (or click Play button below)

University Nebraska Extension - Japanese Knotweed (or click Play button below)

Means of Introduction: Introduced as an ornamental and for erosion control

Impact: Crowds out native species

Current U.S. Distribution:

• Northern Distribution Map (PDF | 233 KB) / Invasive Species Maps
  USDA. FS. Northern Research Station.
• 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: Invasive Plant Atlas of the United States map

Management Plans: Plants / Knotweeds

Selected Internet Resources:

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

Fallopia japonica var. japonica
Integrated Taxonomic Information System.
Taxonomy

Japanese Knotweed - Plant Invaders of Mid-Atlantic Natural Areas (2002)
DOI. National Park Service and Fish and Wildlife Service.
Identification/Description; Photographs; Distribution; Introduction History; Impacts; Controls

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

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

Japanese Knotweed - Biological Control of Invasive Plants in the Eastern United States (Aug 2002)
BugwoodWiki.
Published by: USDA. Forest Service. Publication FHTET-2002-04.
Taxonomy; Identification/Description; Photographs; Distribution; Introduction History; Impacts; Life Cycle; Habitat; Controls

Japanese Knotweed - Pest Alert
USDA. FS. Northeastern Area.
Identification/Description; Photographs; Impacts; Distribution

Japanese Knotweed - Weed of the Week (Sep 14, 2004; PDF | 196 KB)
USDA. FS. Northeastern Area. Forest Health Protection.
Identification/Description; Photographs; Introduction History; Impacts; Habitat; Distribution; Controls

Japanese Knotweed - A Field Guide for the Identification of Invasive Plants in Southern Forests
USDA. Forest Service. Southern Research Station.; Bugwood Wiki.
Identification/Description; Photographs; Distribution; Controls

Managing Japanese Knotweed (2007; PDF | 923 KB)
USDA. NRCS. Conservation Reserve Enhancement Program; Pennsylvania State University.
Identification/Description; Photographs; Dispersion; Controls

Plant Profile for Polygonum cuspidatum - PLANTS Database
USDA. NRCS. National Plant Data Center.
Taxonomy; Illustrations; Distribution; Legal Aspects

Polygonum genus - EncycloWeedia
California Department of Food and Agriculture.
Identification/Description; Photographs; Habitat; Distribution; Dispersion; Controls

Japanese Knotweed - Invasive Plant Species Fact Sheet (PDF | 734 KB)
Indiana Department of Natural Resources. Invasive Plant Species Assessment Working Group.
Identification/Description; Photographs; Introduction History; Habitat; Distribution; Controls

Japanese Knotweed - Invasive Plants of Ohio
Ohio Department of Natural Resources. Natural Areas and Preserves.
Identification/Description; Photographs; Introduction History; Impacts; Habitat; Distribution; Controls

Japanese Knotweed aqnd Giant Knotweed
Pennsylvania Department of Conservation and Natural Resources. Invasive Exotic Plant Tutorial for Natural Lands Managers.
Identification/Description; Photographs; Introduction History; Impacts; Habitat; Special Note: Species Management and Control Information

Japanese Knotweed - Vermont Invasive Exotic Plant Fact Sheet (PDF | 94 KB)
Vermont Agency of Natural Resources. Environmental Conservation.
Identification/Description; Illustrations; Introduction History; Impacts; Distribution; Controls

Japanese Knotweed - Invasive Alien Plant Species of Virginia (PDF | 99 KB)
Virginia Department of Conservation and Recreation. Natural Heritage Program; Virginia Native Plant Society.
Identification/Description; Illustrations; Introduction History; Impacts; Habitat; Distribution; Controls

Japanese Knotweed - Non-Native Freshwater Plants
Washington State Department of Ecology. Water Quality Program.
Identification/Description; Photographs; Introduction History; Impacts; Habitat; Distribution

Class B Noxious Weed: Japanese Knotweed
Washington State Noxious Weed Control Board.
Taxonomy; Identification/Description; Photographs; Impacts; Habitat; Distribution; Dispersion; Controls; Legal Aspects

Japanese knotweed and other knotweeds - Invasive Plant Species of Alaska (PDF | 304 KB)
University of Alaska - Anchorage. Alaska Natural Heritage Program.
Identification/Description; Photographs; Impacts; Life Cycle; Distribution; Dispersion; Controls

Polygonum cuspidatum (Japanese knotweed, Mexican bamboo) - Invasive Plant Atlas of New England (IPANE)
University of Connecticut. Ecology and Evolutionary Biology.
Taxonomy; Identification/Description; Photographs; Introduction History; Distribution; Dispersion

Japanese Knotweed - Invasive Plant Atlas of the United States
University of Georgia. Center for Invasive Species and Ecosystem Health.
Taxonomy; Identification/Description; Photographs; Introduction History; Distribution

Fallopia japonica (Japanese Knotweed)
University of Massachusetts - Boston. Biology Department. Conservation New England.
Identification/Description; Introduction History; Distribution; Special Note: Animation of spread of Japanese Knotweed across Massachusetts over time

Japanese Knotweed / Mexican Bamboo - Maine Invasive Plants Bulletin no. 2511
University of Maine Cooperative Extension.
Identification/Description; Photographs; Introduction History; Impacts; Habitat; Distribution; Controls

Japanese knotweed - Introduced Species Summary Project
Columbia University. Center for Environmental Research and Conservation.
Taxonomy; Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Controls

Japanese Knotweed - Ohio Perennial & Biennial Weed Guide
Ohio State University. Ohio Agricultural Research and Development Center.
Identification/Description; Photographs; Introduction History; Life Cycle; Distribution

Japanese and Giant Knotweed - Fact Sheet: Invasive Weeds (PDF | 237 KB)
Pennsylvania State University. Cooperative Extension.
Identification/Description; Photographs; Dispersion; Controls

Fallopia japonica - Invasive Species Compendium
Centre for Agricultural Bioscience International (CABI).
Taxonomy; Identification/Description; Photographs; Impacts; Life Cycle; Habitat; Distribution; Controls

Japanese Knotweed Alliance
CABI Bioscience.
Taxonomy; Photographs; Impacts; Life Cycle; Distribution; Controls

Fallopia japonica- Delivering Alien Invasive Species Inventories for Europe
European Commission. Sixth Framework Programme.
Taxonomy; Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Distribution; Dispersion; Controls

Fallopia japonica - Invasive Alien Species Fact Sheet (PDF | 700 KB)
North European and Baltic Network on Invasive Alien Species.
Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Distribution; Dispersion; Controls

Japanese Knotweed
Cornwall County Council (United Kingdom).
Identification/Description; Photographs; Impacts; Life Cycle; Dispersion; Controls; Legal Aspects

Fallopia japonica (herb, shrub) - ISSG Global Invasive Species Database
World Conservation Union. Invasive Species Specialist Group.
Taxonomy; Identification/Description; Impacts; Life Cycle; Habitat; Distribution; Controls

Japanese Knotweed - Invasive Exotics (PDF | 50 KB)
Bowman's Hill Wildflower Preserve (Pennsylvania).
Identification/Description; Illustrations; Distribution; Dispersion; Controls

Polygonum cuspidatum
Discover Life.
Identification/Description; Photographs; Illustrations; Introduction History; Impacts; Life Cycle; Habitat; Distribution; Dispersion; Controls; Legal Aspects

Japanese Knotweed - BioBullies (Western Pennsylvania)
Natural Biodiversity.
Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Controls

Japanese Knotweed
Plant Conservation Alliance. Alien Plant Working Group.
Identification/Description; Photographs; Introduction History; Impacts; Life Cycle; Habitat; Distribution; Dispersion; Control

Japanese Knotweed - Southeast Exotic Pest Plant Council Invasive Plant Manual
Southeast Exotic Pest Plant Council.
Identification/Description; Introduction History; Impacts; Life Cycle, Habitat; Distribution; Controls; Special Note: References