Pruning Tips for Spring Flowering Shrubs

By Lois Scott, Master Gardener

Spring finally arrived and is now quickly passing, as are the blossoms on spring blooming shrubs such as Forsythia, Lilac and Bridlewreath Spiraea. Once these shrubs are finished blooming, we can ensure that next year’s blossoms will be abundant by pruning them effectively.

These shrubs flower best on the wood that grew the previous summer and they benefit from some yearly pruning done right after blooming and before new growth begins. The general idea is to prune out some of the oldest wood each year so that your shrub is renewed over time and does not become overgrown and underperforming. Along with the following tips you should always prune any material that is dead, diseased or dying when you find it.

Lee Reich, the author of “The Pruning Book” recommends the following pruning process.

Cut to within 1 ft (or less) of the ground some of the oldest stems.
To keep your clump to a desired size, selectively cut some of the oldest stems from around the edge of your clump.
If desired shorten some of the remaining older stems. This will keep your shrub short enough that blossoms will be more accessible.
If you have just planted a new shrub this spring, the recommendation is not to do any pruning while plants are young. Just mulch, water and weed your shrub, pruning only material that is dead, diseased or damaged. Pruning stimulates growth and for a young shrub it is important for the energy to go towards root growth.
Use loppers and hand pruners rather than hedge trimmers.

I agree with Lee when he says “it’s best to use your pruning tools to coax a bush along in the direction of its natural inclinations” rather than trying to contain naturally arching shrubs into ‘balls’. Planting shrubs in locations where they have room to grow into their natural shape is preferable to me, however pruning can be a creative pursuit so each to their own!