The perfect time to prune is when they are starting back to growth. I recommend waiting until perhaps April or May so they are in growth. You are likely to get fewer branches at this time of year.

Yes, I agree with Jerry, spring is better time for pruning. Can't wait to chop all my plants, they're so ugly right now. Ahhh....

agreed. wait until growth starts, and you will be amazed to see them take off ...