Certified GKH Gardening Expert
With freeze-damaged plants, the best thing to do is protect them from further freeze damage, then leave them until spring. Waiting until spring to prune will prevent additional damage from the cold, and you will be able to see which parts of the plant are still alive (those that produce leaves) and which are dead. You can then prune away the dead parts.
If the whole plant looks dead in spring, this plant can even be pruned to the ground, and it may still grow back from the roots.