Why to prune in the first place? Many spring-flowering shrubs become straggly, take up more space, become horribly shapeless and will flower less unless pruned every year.
Cutting out the deadwood allows the plant to breathe more and allows light into the interior for healthier growth and less danger of disease.
“The basic rule of thumb is that if a plant flowers before mid-June, prune it in the spring after flowering; if it flowers later, prune it in late winter or early spring.” -GardenersPath
In other words, if you have any summer flowering plants they will need to be pruned in the spring. Even late summer blooming plants can benefit from a light pruning too. Cutting off any deadwood from trees, shrubs or flowering plants will be beneficial as it will open them up for oxygen and light which will in turn create growth.