Pruning should enhance the natural shape and performance of your shrub. But if you are happy with the size, shape and performance of a shrub, you don’t need to prune it! Simple as that!
Reasons to Prune:
When you select your flowering shrubs take in consideration how big the plant can grow (the ultimate size) and also where you want to place it! That will make your gardening much easier, you will have less care and less pruning!
Pruning can’t be done any time. Avoid pruning any flowering shrub in late summer or autumn because this can stimulate tender new growth and this can be damaged by cold temperatures.
Knowing if your plant flowers on new or old wood, helps you determine when it’s the best time to prune.
Spring flowering shrubs (early blooming plants such as Forsythia, purple Sandcherry, Flowering Almond, Llilac and Mockorange) bloom on “old wood” (on the previous season’s growth). In other words, the flowers actually developed on the plant late last summer. For maximum flower production next year, prune spring flowering shrubs immediately after they bloom.
Summer and early-autumn flowering shrubs (such as Butterfly Bush, Potentilas, Spireas, Rose of Sharon, Hydrangea paniculata) bloom on the current season’s growth or “new wood”. These plants should be pruned in late winter or just as growth starts in spring.