Yes, in general perennials in a cold climate will have top growth that has died in the winter and it cleans up the garden to trim back any of the brown, black or dead stems, leaves and top growth. You may see signs of green new growth sprouting. You can leave the new growth but if you accidently cut this back as well don't worry. The perennials will try again to sprout with fresh new growth. Keep growing, Marianne Binetti