When lilac flowers reach their peak and are just this side of fading out, cutting.
Sep 21, Prune severely to revive an old tree in the winter months when the tree is dormant. Some flowering branches will be sacrificed, but if you take three years, removing only a portion of the old wood each year, you can keep your lilac blooming while you revive it. Remove one-third of the old growth the first winter. Cut it back to the ground. Old, neglected lilacs can be renewed or rejuvenated by pruning.
Home gardeners can choose between two different pruning methods. One way to renew a large, overgrown lilac is to cut the entire plant back to within 6 to 8 inches of the ground in late winter (March or early April).
Jul 08, Japanese tree lilacs generally require little, if any, pruning until they are about 3 years old. After this, any necessary pruning should be done immediately after the flowering period is over. Remove dead or diseased branches, as well as any branches that interfere with the overall vase free tree mulch berkshires or clutter the interior of the tree. Jun 26, 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 Estimated Reading Time: 4 mins. Mar 26, Remove all old and dead wood, hard prune any remaining limbs to about 2-feet, and thin the suckers to leave only the strongest. Remove the trees entirely and plant something that prefers shade. In either case, I would have no Lilac blooms in April, but in fact, I had none anyway.