Apr 02, When to Trim Lilac Bushes. Knowing when to trim lilac bushes is important. 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. Nov 27, If a lilac bush has become extremely overgrown, plan on cutting back the plant over a period of three years. Each year after the flowers have bloomed and died, prune one-third of the lilac. Begin by cutting off the oldest branches first. A severely overgrown bush may also be pruned down to the ground.
Jun 14, How far down do you cut a lilac bush? Answer this question + 4.
Answered. Do you trim just the top or half way down after your bush is done with its spring flowers or can you make a lilac bush bloom all summer long? 6 answers Josh Joslin on Jun 14, Prune out all dead limbs first. Old, overgrown lilacs, like mine, require more drastic pruning.
In early spring before growth began, I headed out to take a good look at the bush. Before I started cutting, I checked to see if the plant had been grafted. Since it hadn’t, I cut it right down to the ground (for a grafted plant, see the panel below).