Last year my neighbor gave me (two) butterfly bushes from her garden. I believe they are called Black Knight. They are about 2ft tall. Just looking at them, I noticed that the branches look like dead twigs. They're dry, brittle and no green. I've never had BB bushes before so I'm not familiar with their growth habit. Do new shoots grow out of the ground or off the branches? When should I notice some new growth? Should I prune them shorter? Help please? Thanks.