We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. Please consider making a contribution to wikiHow today. St. John’s wort (common) is a perennial herb with medicinal properties. These cookies do not store any personal information. This category only includes cookies that ensures basic functionalities and security features of the website. Thor Sturluson has a BS in Biology, majoring in Botany, from the University of Maine and a masters degree in Zoology from the Open University in London. St. Johns Wort (a native of Europe) occurs commonly along roadsides and hedgerows, and this herb has one of the most glamorous histories in the plant kingdom.