May. 18, 2018

common St. John's-wort, Hypericum perforatum

There's a fine line between innocent invasives and damaging invaders. Common St. Jon's-wort sits right on it. It has never gotten to the point of dominating our habitats, and overwhelming native flora like too many others have. And it's certainly an attractive plant. But it's not so innocent. It is poison, particularly to grazing animals. Being poison, of course humans consume it as medicine. Derivatives are a popular and somewhat effective treatment for depression. St. John's-wort has been reported from open areas in every state except AK, AL, AZ, FL, and UT, from BC, MB, NB, NF, NS, ON, PE, QC, SPM, and a great many other countries around the world. In some it has made it across the line to being listed as invasive, pushed in part by its effect on livestock. Lenawee Co MI, 7/7/13.