$5 in a 9cm pot
Not used as a medicinal herb now but back in the day it was thought to cure you of moonstruck madness (there was a thing!) but also ironically, it was also cultivated as it was believed to be able to bewitch you; by gazing apon the plant in moonlight it would enable you to become transformed into an aerial being.
Wanna give it a go?? The bees will love you for it in the meantime!