Q.I want to prune and cut back branches on my Hemlock. the tree is getting too wide.
How far can I cut a branch from its tip towards the trunk of the tree?? If I cut a branch past its needles into the wood, will that hurt the branch? Will it still grow? I was told that you can cut a branch back one third of its length and it will still grow. is that true?

Don't remove more than 25% of the branch, or of the entire foliage in a one year period, is the rule of thumb for best management practices in pruning.
Be conservative and don't remove all the foliage on a branch, leaving a bare stub. It's ugly and on a conifer it may not re-foliate.