Pruning flowering shrubs at the wrong time can remove a whole season of buds. A lilac may grow plenty of healthy leaves after a late trim and still produce few flowers the following spring. In a mixed Mankato border, the right week to prune one plant may be the wrong week for its neighbor.
Find out where flowers form
Some shrubs set flower buds on stems that grew the previous year. Lilacs are a familiar example. As a rule, trim spring bloomers after they finish flowering so they have time to grow and set the following year’s buds.
Other shrubs flower on the current season’s growth. Their timing can differ even when they sit beside a lilac. Identify the plant, and its variety when you can, before choosing a pruning window. A photo of the flowers often helps more than a winter picture of bare stems.
Decide what each cut should achieve
Stand back and look at the outline. Do you want more light through the center, room beside a walk or simply a clear view from a window? Choosing one goal helps avoid trimming every branch to the same length by habit.
For a lilac that has grown dense, ask about gradual thinning. Removing selected older stems can open space for younger growth. A close shearing across the outside creates a different effect and may leave the crowded interior in place.
Keep a simple bloom record
Take a picture when the shrub flowers, then another when the blooms fade. Mark its location in the bed. Two shrubs that look alike in January may have very different flowers and schedules in May.
Use the University of Minnesota’s spring pruning guidance to plan the conversation. When requesting shrub trimming, share the photos and the shape you want to keep. That gives the crew a clear goal before the first cut.