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. 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 treelop.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 shaping. Jun 10, To prune lilacs, get to work in the spring: cut fresh flowers for bouquets, nip off the longest stems, and thin out any weak stems at the base.
Avoid pruning late in the summer or fall since doing so can limit future treelop.buzz: K. Nov 17, The best time -- and only correct time, really -- to prune lilacs is just after blooming. All shrubs fall into one of two categories; some, like many of the hydrangeas, bloom exclusively on new wood and can be pruned to the ground each fall if required.
Timing is the Decisive Factor in Pruning Lilacs. If you want to have your blooms next year, it is crucial to prune in those first few weeks after blooming ends. Ideally, this is when you would do maintenance pruning each year. But I get so lazy busy, I end up with a.