Cut back perennials

Cut out standing stems and decrepit greenery. Your targets are anything that is not going to grow and won't rot away quickly. Cut right down to the ground. New growth will come from perennials' crowns.

Lenten rose as an example

The leaves last 12 months, then die back as the flowering stalks stand up to bloom and new leaves grow. Some times the winter is very rough on that foliage. If the old leaves are tattered and brown, cut them away. The blooms will look much better with that distraction removed.

And then, they'll look like this: