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St. Johnswort (Hypericum perforatum) 

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These medium-tall plants have loose clusters of somewhat dull yellow flowers, each with five petals and a dense patch of many stamens.  Leaves grow opposite each other and the upper plant is often multi-branched.  There are about dozen species in Michigan, five of which occur throughout the state.  Only H. perforatum is an exotic, and is (maybe) the most abundant.  One species is on the Michigan threatened plant list (H. sphaerocarpum).   Herbal medicinal qualities have been ascribed to St. Johnswort, including treatment for insomnia, mild depression, and bedwetting. 


yellow_flower_md_wht.gif Return to the Yellow Flower Page, or to the Michigan Invasive Plant Council home page.

This website is maintained by Bill Cook in cahoots with the Michigan Invasive Plant Council (MIPC).  The MIPC is a loose group of folks (not necessarily a group of loose folks!) working to make information available about invasive plants in Michigan and related issues.  If you have questions or comments about the information on this page, contact Bill

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