Regular pruning of plants keeps growth under control. While many homeowners fear they will prune too much from a plant and cause damage, this is unlikely. Fewer prunings will cause more damage than one hearty one. Lilac bushes are common shrubs in the Midwest United States. They thrive on the cold winter climates to produce fragrant blooms in the spring. Pruning a lilac tree back to its shorter bush counterpart will allow the plant to produce even more blooms.
Prune the lilac after the spring blooming season has ended. Lilacs begin to form buds for the following year directly after blooming. Prune in early summer for optimal growth of the lilac. This will allow for proper bud germination for the following summer.
Cut the top-most branches of the lilac tree with a pole pruner. Place the cutting edge near the edge of a stub and pull the cord to cut the branch at an angle. Continue heading back the top branches until the tree has reached the bush height desired.
Prune lower branches with lopping shears. When heading back, or shortening to a bud, branches place the shears above a stub and cut. Never cut directly on a stub or below it. This will cause damage to the plant and stunt growth of the branch.
Thin any necessary branches to the trunk. Place the lopping shears at the base of the branch, next to the trunk. Do not shear completely even with the trunk, but instead cut 1/4 inch from the trunk, removing the branch. Leaving a small nub at the trunk base protects the bush from the intrusion of insects and disease. Continue thinning branches until the desired bush size is achieved. For larger branches over 1 inch, use a pruning saw.
Cut removed branches with the lopping shears or a pruning saw and dispose of them.