Jul 08, Start by taking out the thickest stems first. Although you'll be losing some flowers for the current year, pruning overgrown lilacs is easiest early in the spring before the branches leaf out.
After three consecutive years of pruning your overgrown lilac. Jun 19, Knowing when to trim older lilac bushes is important. Most lilacs don’t require pruning until they reach about 6 to 8 feet tall.
The best time for pruning older lilac bushes is right after their flowering has ceased. This allows new shoots time to develop the next season of blooms.
Pruning too late can kill young developing treemulch.buzzted Reading Time: 3 mins. Oct 06, You should resist the temptation to prune or trim your lilac bush until it is at least 6 ft. tall, which typically occurs during the second or third year of growth. At this point, there will be enough excess stems and blooms for optimal treemulch.buzzted Reading Time: 6 mins. 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.