Pruning of trees and shrubs is done to promote strong, healthy and attractive plants by removing structurally weak, diseased, dead or broken branches. An exception may be when pruning to correct interference with infrastructure: power lines, walkways, etc.
Timing is of the utmost importance when pruning - early spring, before bud break, is considered to be the best time to prune as this provides ample time for promotion of wound closure (compartmentalization). With flowering shrubs this will result in diminished flowering. How much will depend on the amount of pruning. However, the structural effect of the shrub should be considered more important than flowering. Also, the lack of leaves at this time is an aid to proper selective pruning. Pruning may, of course, be done at other times of the year, however, at the sacrifice of speedy wound closure which could impact the health of the plant.
Remove old, non-productive and dead branches from the flowering shrubs base, but never shear. When deciduous shrubs become overgrown or thinned at their bottom they can be rejuvenated if their health is good.
Any of three methods may be employed for rejuvenative pruning and should be done between mid February to mid April.
Any of the above methods used will result in new basal shoot growth. These canes should be cut back to differing lengths, removing obvious weaker shoots, which will result in the development of a stronger, healthier plant.
When the pruning operation is for trees no work should be attempted that is not within the reach of a pole saw or pole trimmer when used from ground level.