St. John's Wort is a short-lived perennial, 5-6 years, that is a short, woody shrub that grows between 2-3 feet tall and has fragrant yellow flowers from mid to late summer. St. Johns wort's name apparently comes from John the Baptist, and historically has been used to ward off evil spirits and witches. The oil in the leaves have been used topically for wounds, sunburns, and general aches and pains. The plant has also been used to treat mild depression and insomnia with some success.