I think the only thing that can kill a peony is root rot. Alot of the hybrids are rather susceptible to this but the lactifloras are pretty tough. There are some peonies that you cannot kill even having it dug up. These are the ones that have adventitious roots and these roots have eyes that resprout even after the parent plant is gone. Ellen Cowley peony is like that. I have two plants originated from my original plant and they are both blooming size already.
