Aconitum napellus

Monkshood - Ranunculaceae - deadly poisonous ! - ancient times hunters / archers  tipped their spears / arrows with Monkshood - used in murder plots - Europe Asia North America - herbaceous perennial - height 2m - dark purple to blue flowers look like monks hoods - medicinal uses - zone 3-7 - sun part shade - July August - rich moist well drained