Cedar hedges are quite easy to prune provided you follow these guidelines:
First prune lightly and more often. A typical well established cedar hedge may require 2-3 prunings per year. Do not prune into the old, heavy wood as it will not normally re-grow. You will be left with bald, bare patches of hedge until the surrounding newer growth can cover it over.
Second, start your pruning in mid spring and then depending on growth again in early summer and then perhaps mid fall. Keep your pruning cuts clean. If you have ragged edges or broken branch tips, those will turn brown and become unsightly.
Third, prune so that the top of the hedge is smaller and thinner than the bottom. This will ensure that all parts of the hedge receive an adequate amount of light. Any part of the cedar that does not receive light will eventually brown and fall off (something you don't want!)
If you have any other questions about hedge pruning, give us a call at 604.882.1201 or visit Arts Nursery Ltd in person.