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National Invasive Species Information Center
U.S. Department of Agriculture
Home / Terrestrial Invasives / Terrestrial Plants / St. Johnswort / St. Johnswort Resources

St. Johnswort Resources

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Alaska Exotic Plants Information Clearinghouse (AKEPIC): Species Biography - Common St. Johnswort (Feb 7, 2011) (PDF | 128 KB)
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)
Class C Noxious Weed: Common St. Johnswort
Washington State Noxious Weed Control Board.
Early Detection & Distribution Mapping System (EDDMapS) - Common St. Johnswort
University of Georgia. Center for Invasive Species and Ecosystem Health.
Provides state, county, point and GIS data. Maps can be downloaded and shared.
Encycloweedia: Data Sheet - Common St. Johnswort or Klamathweed
California Department of Food and Agriculture.
See also: Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources
Exotic Species: St. Johnswort (2010)

DOI. NPS. Science of the American Southwest.

See also: Invasive Plant Species for more fact sheets
Fact Sheet: St. John's-wort (Jan 2014) (PDF | 851 KB)
Alberta Invasive Species Council (Canada).
See also: Fact Sheets for more information about individual invasive species, including those listed as "Prohibited Noxious" and "Noxious" under the Alberta Weed Control Act
Fire Effects Information System (FEIS) - Hypericum perforatum
USDA. FS. Rocky Mountain Research Station. Fire Sciences Laboratory.
Global Invasive Species Database - Hypericum perforatum (herb)
IUCN. Species Survival Commission. Invasive Species Specialist Group.
Google Images - St. Johnswort
Google.
Invasive Plant Atlas of the United States - Common St. Johnswort
University of Georgia. Center for Invasive Species and Ecosystem Health.
Invasive Plants: Other Invasive Plants - St. John's Wort

Business Queensland (Australia).

Invasive.org - Common St. Johnswort
University of Georgia. Center for Invasive Species and Ecosystem Health.
MontGuide - St. Johnswort: Identification, Biology, and Integrated Management (2017)
Montana State University Extension.
Noxious Weed Species - Common St. Johnswort

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

NSW WeedWise: St John's Wort
New South Wales Department of Primary Industries (Australia).
Ohio Perennial & Biennial Weed Guide - Common St. Johnswort
Ohio State University. Ohio Agricultural Research and Development Center.
Pacific Island Ecosystems at Risk (PIER) - Hypericum perforatum
USDA. FS. Institute of Pacific Islands Forestry.
PLANTS Database - Common St. Johnswort
USDA. NRCS. National Plant Data Center.
Poisonous Plants - St. Johnswort
USDA. ARS. Poisonous Plant Research Laboratory.
St. Johnswort: Identification, Management and Control
University of Nebraska - Lincoln. Cooperative Extension.