Prune themout as low as you can get, or as near the main stems as possible. Some lilacs produce many new shoots from the base (watershoots or suckers). Remove all but a few of these each year, leaving ones to make new brancheswhere you want, and that don’t rub on others. Apr 02, Most lilacs don’t require pruning until they reach about 6 to 8 feet ( m.) tall. The best time for pruning lilac bushes is right after their flowering has ceased.
This allows new shoots plenty of time to develop the next season of blooms. Pruning lilacs too late can kill young developing buds. If you are pruning lilac trees or shrubs entirely to within inches of the.