ROADWEEDS OF THE UPPER PENINSULA
|St. Johnswort (Hypericum perforatum)|
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.
Return to the Yellow Flower Page, or to the Michigan Invasive Plant Council home page.
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