On the surface, this is a good and challenging question. However, with a little research and the help of this article, you will quickly and easily learn the best way to handle it.
Dead, diseased, or injured branches may be pruned at any time of the year to minimize further problems and improve aesthetics. However, heavy pruning such as Renovation Pruning, Selective Thinning, Heading-back, etc.… should be done at more specific times of the year based on when the plants bloom.
Spring flowering trees and shrubs make flower buds for the next year during the summer months, and pruning them in the fall would remove the buds. This results in reduced flowers the following spring. It is best to prune these after they finish blooming. Some examples of spring-flowering trees and shrubs are Saucer Magnolia, Dogwood, Azalea, Bigleaf Hydrangea, and many others.
Summer-flowering trees and shrubs bloom on the current year’s growth, (meaning that as the new growth begins in the spring they begin creating buds for summer blooms). So, these are best pruned in late winter before the spring growth begins. A few examples of summer-flowering trees and shrubs are Crape myrtle, Rose-of-Sharon, Japanese Spirea, and Gardenia.
Fall pruning of any trees or shrubs can stimulate new tender growth that can be burnt by freezing temperatures and cause damage to the plants overall.
Adhere to the guidelines for pruning in South Carolina as described by the Clemson University Home & Garden Information Center. Pruning techniques and styles are described in better detail in the “Pruning Trees” Fact Sheet available by clicking HERE