Is it a herbaceous peony (these die to the ground in winter) or a tree peony? If it's the latter, don't cut it down at all. If it's the former (which are more commonly grown), then threegardener's advice is great. Peonies also have fall colour that would be shame to miss.
I would like to know if anyone in my area Stratford CT has a Californian Lilac ,a friend has one in the Uk know they originate in California ,but wondering about the cold temps WE get here
This is my friends in Coventry UK