Do nothing until they begn to grow in the late spring. Then if the frosts have killed off the top growth (which usually happens unless you live somewhere very mild) you will see new shoots appearing at the base of the plant and you can cut last years growth back to the ground. If the branches are regrowing leaves you can choose whether to cut them and how far back. If you leave them they do flower a bit earlier.

If they are hardy ones and they are outside they may well get 'knocked back by the frosts but will re-sprout from the ground. Cut the dead wood out April time. If they are semi-hardy then don't prune until April and then remove any dead damaged wood that there is using either a sharp knife or secateurs.

welcome to GOY too.