The best time to prune a shrub is during the dormant season. It is easier to see the shape of the shrub when the leaves have fallen. Not all pruning of spring flowering shrubs should be done while the shrub is dormant, though. Pruning at the wrong time will cost you blooms. By knowing when to prune, your spring flowering shrubs will give you many years of enjoyment.
Structural Pruning
Late winter/early spring is the best time to prune for the following problems:
- Crossed or Rubbing Branches
- Rejuvenation
- Suckers
- Dead, Diseased or Infested Wood
For more information, check out: Pruning and Cutting Guide
Prune for Blooms
Spring flowering shrubs begin forming next year’s bloom shortly after they are finished blooming. You have a small window of opportunity to prune before you start sacrificing blooms. Thin out a shrub by pruning the ends of branches back, cutting just above a side bud. This will help the shrub grow in a compact shape and will be more upright. Shrubs that have flower clusters, such as lilacs, usually need to have the spent clusters pruned back to encourage more blooms the following year.
Check Out: Time for Spring Landscape Gardening
Rejuvenating an Overgrown Lilac
Lilacs are prone to the problems of becoming overgrown. Rejuvenating a lilac is done over a span of three or four years. Start by removing one or two of the oldest, most overgrown branches as close to the ground as you can. This will open up your lilac, allowing sunlight to reach the new growth near the base of the shrub. Continue removing the oldest branch or two for the next couple of years. Continue removing spent flower clusters and soon you will have a shorter shrub that is easier to take flower cuttings from. Remember that lilacs bloom on year old wood; don’t take too much new growth when you gather flowers.