St John's Wort grows wild as a weed where I live. Way back when I would harvest the golden flower tops when they'd bloom around the time of la fete de Saint Jean Baptist, which is how it got its name, and dry them upside down and then keep just the flower tops. If you drank a tea made just from that, you'd go straight to sleep and sleep very deeply. Only works with the dried flowers made at home. None of the store bought forms or other parts of the plant had that effect. I didn't use it, only kept it for emergencies, last resort, but worked like a charm.