You can safely prune just about any flowering shrub soon after flowering has stopped to avoid trimming off the following year’s blooms. If you aren’t sure and your number one concern is bloom loss prune at this time. If you are more concerned about the plant than the flowers, pruning during dormancy is an ideal time for pruning almost any plant.
When to Prune Flowering Shrubs
When to do Light Pruning
You can trim flowering shrubs lightly anytime of the year. Light pruning includes removing dead or broken branches, minor shearing, and removing spent blooms (deadheading).
When to Prune Spring Flowering Shrubs
Bushes that bloom before June 15th should be pruned soon after flowering has ended. Spring bloomers, especially the early spring blooming shrubs, generally bloom on old wood. Do not prune these bushes in winter or early spring when you are likely to remove young flower buds. Azalea, Barberry, Forsythia, Lilac, Ninebark, Rhododendron, Viburnum, Weigela, and Wisteria are some examples of spring flowering bushes.
When to Prune Summer Flowering Shrubs
When to Prune Hydrangeas
Hydrangeas can bloom on old or new wood and some newer varieties even bloom on both! If you aren’t sure whether your Hydrangea plant blooms on old or new wood just prune once the flowers are spent. Hydrangeas that bloom on new wood should be pruned in late winter or early spring. Hydrangeas that bloom on old wood should be pruned once blooming has stopped and the flowers are spent. Hydrangeas bloom in summer and/or fall. Read more about when to prune hydrangeas.
When to Prune Camellias
Camellias are fall and winter blooming flowering shrubs. Some varieties actually flower well into spring. These evergreen flowering shrubs vary in their bloom time. Camellias don’t generally require pruning, but can tolerate even heavy pruning. Prune Camellias after flowering has ceased.