Taxon  Report   4312 
Hypericum perforatum  L.
Common st. johnswort,  Klamath weed, Klamathweed
Hypericum perforatum
© 2005 Louis-M. Landry
Click on a photo to see it bigger.
Hypericum perforatum
© 2005 Louis-M. Landry
Hypericum perforatum
© 2008 Keir Morse
Hypericum perforatum, a dicot, is a perennial herb that is not native to California; it was introduced from elsewhere and naturalized in the wild.
It is an invasive plant. The California Invasive Plant Council classifies its potential impact on native ecosystems as moderate (plant profile / CalWeedMapper).

Interactive Distribution Map

Observation Hotline
(observation details + photos)

point, line, or polygon

one or more occurrences
within a 7.5-minute quadrangle

Plant Characteristics
and Associations

Bloom Period
Hypericum perforatum
© 2005 Louis-M. Landry
Genus: Hypericum
Subspecies and Varieties:
weed, characteristic of disturbed places
Habitat: disturbed, disturbed [Walker]
Distribution by County 

Add an Observation of  Hypericum perforatum

Name Status:
Accepted by TJM2 + PLANTS + JM93
More information about  Hypericum perforatum
Photos on CalPhotos / Google Images
Photos and ID tips from

Jepson eFlora

Records from the Consortium of California Herbaria

Original Publication citation (ITIS)


Search the International Plants Names Index

Search (Flora of North America)

website references from Google

Suggested Citation
Calflora: Information on California plants for education, research and conservation,
with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria.
[web application]. 2016. Berkeley, California: The Calflora Database [a non-profit organization].
Available:   (Accessed: Oct 27, 2016).

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