Unfortunately, as lilacs mature, the shaded lower portions of the shrubs usually.

Apr 02, Most lilacs don’t require pruning until they reach about 6 to 8 feet ( m.) tall.

The best time for pruning lilac bushes is right after their flowering has ceased. This allows new shoots plenty of time to develop the next season of blooms. Pruning lilacs too late can kill young developing buds. If you are pruning lilac trees or shrubs entirely to within inches of the ground, it is best to do so in early spring. Jul 08, The time to prune mature lilac plants is just after the flowers have faded in the spring.

Lilacs set next season's flower buds almost immediately, so late pruning will mean sacrificing the next year's flowers.   Pruning early also gives new shoots more time and energy to develop, ensuring plenty of blooms for the following spring.