Growing/CareVery drought tolerant. Add to Cart. Cheery perennial herb with a long history of medicinal use. The flower tops are harvested when the majority of the buds are open. St. John's Wort can be identified by the tiny pin-prick holes in its leaves which can be seen when held up against the sky. Packets are 3.25" wide by 4.50" tall and come with a full colored illustration on the front side, as well as detailed sowing instructions on the reverse. The use of Wort as a medicinal herb dates back to the ancient Greeks. 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.