To prune an overgrown cedar tree, remove all dead and diseased limbs, cut back awkward branches, and shearing the outside of the tree, states the San Francisco Chronicle. Slowly control an overgrown tree through pruning over the course of several years.
Prune the tree lightly in the spring, advises. First, find the dead zone of the cedar tree. The dead zone is located in the interior of the tree where light is scarce and is characterized by a lack of needles. Because no new growth appears in the dead zone, avoid cutting into it. After finding the dead zone, shape the tree by only trimming greenery from branches in the live zone.
Remove all dead, damaged and diseased limbs in the live zone, states the San Francisco Chronicle. Cut the branches back to the nearest green shoot or to the trunk if necessary. After removing diseased limbs, sterilize the pruning shears with rubbing alcohol to keep disease from spreading to the rest of the tree.
During mid-summer, it is important to shear the greenery on the outside branches, according to the San Francisco Chronicle. Only remove up to 3 inches of greenery per branch. Do not shear the top of the tree.