Prune hedges in late winter with a tapered shape so the top is narrower than the base. Thin inner branches when you cut the hedges back to allow sunlight in the middle.
Cutting back hedges leaves the plants healthier and helps shape the hedges. Most hedges naturally grow wider at the top because that area receives the most sunlight. This blocks the sunlight to the bottom even more, preventing the lower branches from growing well. Cut back the hedges so the top is the narrowest part with the hedge getting gradually wider at the base. The tapered shape also prevents a large amount of snow build-up on the top in the winter months, which can damage branches.
Later winter is the ideal time to prune, especially if you plan to cut the branches back drastically. If you wait until buds grow, you remove all of the potential new growth. The hedge takes longer to regrow when you cut off the buds.
Hand shears or power trimmers work to cut back hedges. Power trimmers make the job easier and faster if you're doing a large amount of pruning. Use bypass hand pruners to reach inside the hedge to thin out some of the branches so sunlight can penetrate the hedge. Cut out one or two branches every few feet.