We grow and dry St John's Wort on our farm and hand harvest when the plant is bursting with those lovely yellow flowers.
Known as the depression herb many studies have suggested it's positive effect on treating mild depression. It can take several weeks of use before the effects begin to be felt. It is especially useful in treating SAD (Seasonal Affective Disorder).
Lesser known qualities of St John's Wort are it's anti-viral effects. Used both internally and externally to treat viral infections such as chickenpox and shingles.
Consult an experienced herbalists before using large amounts of St. John's Wort as it can counteract certain medications as it has a stimulating effect on the liver.