Answer: There are several reasons why lilacs may fail to bloom. The first reason is lack of sunlight. Lilacs need full sun. Full direct sun all day is best, but at least a minimum of six hours including noontime. Another common reason is pruning at the wrong time. Lilacs bloom on old wood that grew the year before. If you prune in fall or spring, you will be cutting off the blooming wood for the coming season. (The time to prune lilacs is right after they bloom.) Finally, sometimes overfertilizing can cause a lilac to have lots of lush foliage and growth but few flowers. If your lilac is adjacent to a lawn that is heavily fertilized, for example, you would not need to fertilize the lilac in addition to that. I hope this helps you trouble shoot.
Q&A Library Searching Tips