My public service announcement for today is: “Now is the time for all good men and women to come to the aid of their lilacs and trim, shear, thin, and prune them. ” Always prune your lilacs, if they need it, right after they bloom, because if you wait too long after they bloom, you will be removing next years buds.
So if it needs it, do it now! It’s also a good idea to remove a few of the really old branches from within the center of the plant. Below is a link to an article by Fine Gardening Magazine on how and when to prune your lilacs. How to Prune Lilacs by Fine Gardening Magazine