- Hypericum perforatum is a perennial, rhizomatous herb that can reach 4 ft. (1.2 m) in height.
- Leaves are opposite, sessile, elliptic, 0.4-1.2 in. (1-3 cm) long and dotted with many pellucid glands.
- Flowering occurs from June to September, when bright yellow flowers develop at the tips of the stems. Flowers have five petals and many stamens. Petals typically have black glands along the margins.
- The fruits are three-chambered capsules with three persistent styles.
- Ecological Threat
- Hypericum perforatum has been used to treat mild depression, but has been shown to cause hyper photosensitivity. Plants inhabit rangelands, pastures, roadsides and forest clearings. St Johnswort is native to Europe. Hypericum perforatum may be poisonous to cattle in large doses.
- Fire Effects Information System - USDA Forest Service
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EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org
Invasive Listing Sources
- California Invasive Plant Council
- California Noxious Weeds
- City of Ann Arbor Michigan Parks and Recreation
- Colorado Noxious Weeds
- EDDMapS Ontario
- Faith Campbell, 1998
- Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
- Illinois Invasive Plant List
- Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
- John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
- Kentucky Exotic Pest Plant Council - Lesser Threat
- Missouri Department of Conservation,
- Montana Noxious Weeds
- Native Plant Society of Oregon, 2008
- Nevada Noxious Weeds
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- Oregon Noxious Weeds
- Pacific Northwest Exotic Pest Plant Council, 1998
- South Dakota Noxious Weeds
- Tennessee Exotic Pest Plant Council
- Utah Noxious Weeds
- Washington Noxious Weeds
- WeedUS - Database of Plants Invading Natural Areas in the United States
- Wyoming Noxious Weeds
Other System LinksPlants: HYPE
NPDN Pest: PCBABBA
NPDN Host: 36404
|Common Name Reference:|| USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|