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. The best time to prune Denver lilacs is just after the spring flowers have faded. This is because lilacs set the next year’s flower buds immediately after the flowers have died. Late lilac trimming (or early, depending on how you look at it) will kill off these buds, thus the plant won’t produce flowers the next treelop.buzzted Reading Time: 2 mins. May 20, New lilac bushes don't require maintenance pruning until they are about 6 - 8' tall.
The time to prune mature lilac plants is just after the flowers have faded. They set the next season's flower buds almost immediately, so late pruning will mean sacrificing next year's flowers. Jun 19, 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 buds. Deadheading, should. Nov 03, When is the best time to prune my lilac bush and how do I do it? Answer this question + 3.
Answered 5 answers Janice Hale on Nov 03, What I have been told is they should be trimmed within two weeks after they stop blooming. They may not.