The origin of the genus name is murky, with two main theories. One is that it was named after Paeon, a physician to the Greek gods. Another possibility is that it was named after a beautiful nymph named Paeonia.
Another myth about peonies is that they need ants in order to bloom. Ants are attracted to herbaceous peony buds by the sugary nectar found at their base, but those ants chase away more destructive insects. The ants have nothing to do with the actual flowering process. Ants are also found on Itoh peonies but are less likely to be found on tree peonies.