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St. Johnswort

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St. Johnswort
Scientific Name:
Hypericum perforatum L. (ITIS)
Common Name:
St. Johnswort, St. John's wort, common St. Johnswort, Klamath weed, common goatweed, tipton weed
Photo:
St. Johnswort flower, Alaska - Photo by Michael Shephard; USDA, Forest Service
Native To:
Eurasia and North Africa (Zouhar 2004)
Date of U.S. Introduction:
1700s (Zouhar 2004)
Means of Introduction:
Introduced as an ornamental and as a medicinal herb (Klein 2011)
Impact:
Crowds out native species and forage on pasturelands; toxic to livestock (Klein 2011; Zouhar 2004)

Distribution/Maps/Survey Status

Images

Selected Resources

The section below contains selected highly relevant resources for this species, organized by source. To view all related content for this species, click on "View all resources for species" in the top left of this page.

Council or Task Force

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

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.
University of Georgia. Center for Invasive Species and Ecosystem Health.
USDA. FS. Institute of Pacific Islands Forestry.

Federal Government

DOI. NPS. Science of the American Southwest.
See also: Invasive Plant Species for more fact sheets
USDA. FS. Rocky Mountain Research Station. Fire Sciences Laboratory.
USDA. NRCS. National Plant Data Center.
USDA. ARS. Poisonous Plant Research Laboratory.
USDA. ARS. National Genetic Resources Program. GRIN-Global.

International Government

New South Wales Department of Primary Industries (Australia).
Queensland Business and Industry Portal (Australia).
Australian Government. Department of the Environment and Energy.

State and Local Government

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
Colorado Department of Agriculture. Conservation Services Division. Noxious Weed Program.
Lincoln County Noxious Weed Control Board (Washington).
See also: Weed I.D. and Options for Control for more species

Academic

Ohio State University. Ohio Agricultural Research and Development Center.
University of Nebraska - Lincoln. Cooperative Extension.
University of California. Weed Research and Information Center.
See also: Weeds in Natural Areas for more information sheets

Professional

Montana Weed Control Association.

Citations

  • Integrated Taxonomic Information System. Hypericum perforatum. [Accessed Mar 22, 2015].
  • Klein, H. 2011. Common St. Johnswort (PDF | 128 KB) University of Alaska Anchorage, Alaska Exotic Plants Information Clearinghouse.
  • Zouhar, K. 2004. Hypericum perforatum. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.