Plenty of excellent plants need regular pruning. It is a schedule, not a flaw, and the trouble only starts when nobody mentions it.
The most expensive version of that trouble is timing, and it costs more flowers in this valley than frost does.
Spring-blooming plants set their flower buds the previous summer, on last year's wood — lilac, forsythia, mockorange, quince, most viburnum. Prune those in late winter or early spring and the flowers come off before they open. The plant is perfectly healthy and simply never blooms, which is exactly how it gets written off as a bad plant. They get pruned right after they finish flowering.
Summer bloomers flower on the current year's growth — potentilla, butterfly bush, blue mist spirea, most hydrangea. Those get cut in late winter while dormant, and the harder they are cut the better they come back.
Beyond flowering, pruning does three jobs: it takes out dead and crossing wood before it becomes a wound, it keeps light and air moving through a plant that would otherwise shade out its own center, and on young trees it builds the structure that decides whether the tree splits in a storm twenty years later. That last one has a window — it has to happen while the branches are small — and it is the one most often missed.
