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. Therefore, you should prune these shrubs AFTER they have flowered in spring, but before the next year’s flower buds are set.
If you prune these shrubs in winter or early spring, you will remove many of the flower buds. Spring-flowering shrubs that sucker. Jul 08, When to Prune Lilac Bushes. Many of the newer lilac varieties grow quickly and might need pruning starting in their second or third year. In general, by the time a stem reaches more than 2 inches in diameter, it should be pruned. If you are diligent with annual pruning of your lilac, the shrub will grow to about 8 feet tall with flowers throughout the branches.
As soon as the lilac bush's flowers are dead, trim each flower stem back to the leaves, removing all trace of the flowers. This step stops the lilac from using its energy to make seeds. Prune In Late Spring: You must have observed that the lilac bushes bloom only on old growth. Prune them right after they have finished blooming, and before they have started budding for the next year’s show. They are perennial plants that bloom in the spring, Estimated Reading Time: 4 mins.