|Is it too late to prune my lilacs?|
|It's best to prune lilacs in late spring, right after the flowers fade. This will give the shrub all summer to develop new flowering stems. The flower buds are produced at the ends of stems. If you prune now, you may prune off next spring's bloom.
If you must do some trimming, remove some of the oldest stems by cutting them at the ground, and remove any of the suckers that are smaller than a pencil, also by cutting them off at the ground. If you do this every year, you will always have vigorous new growth and the shrub will stay relatively short. You may also remove the spent flowers, although it is not strictly necessary. An overgrown lilac may be cut to the ground all at once, or it may be renewed over several years' time by removing a third of the oldest wood in year one, half of the remaining old wood in year two, and the rest of the oldest wood in year three. Always cut it to the ground and, each year, remove the smallest suckers. Then follow an annual program as described above. Good luck!