Hi PaSue,
I just heard on the news tonight we may get snow showers in a couple of days here in Maryland and there will be cold artic air from Canada.* :X* I would wait until mid April before pruning these plants.* If you prune now you risk frost damage to new growth.* I think your hardiness zone is 6 so it's a bit colder then mine.
Good luck with your knot garden.
Newt
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.