Flowering shrubs are the staple of the home landscape. These anchor plants bloom at various times of the year, depending on the variety of shrub. Forsythia bloom in the spring, heralding the start of summer. Rose of Sharon and crepe myrtle bloom late in the summer. To keep flowering shrubs healthy and blooming perennially, you must perform yearly maintenance to control plant growth.
Look at each plant individually. Just because you're gung-ho to prune at a particular time doesn't mean it's the best time for each plant. Some flowering shrubs should be pruned in early spring while others flower on the previous year's growth. Remember that pruning a flowering shrub should stimulate new growth and flowering.
Examine the plant to determine its general shape. One type of pruning, called thinning, works best for every shrub. Thinning involves the removal of old wood, dead areas and about 1/3 of the plant's old wood growth. If this seems extreme, also consider removal of any branches that don't grow with the natural direction of the shrub. Remove branches that criss-cross inside the shrub and some branches along the base to encourage upward growth at your preference.
Choose the appropriate tool. Clippers can remove branches up to 3/4 inch in width. Loppers can usually clip right through a 2-inch branch. It's important to use the correct tool to prevent damage to the shrub. Pulling or tearing branches for removal only opens wounds in the plant that invite insects and disease.
Grasp the clippers in one hand and the chosen shrub branch in another. To thin the plant, clip the chosen branch as flush as possible with the parent stem at a 45-degree angle. If whole branch removal will mess up the shrub's uniformity, cut at the point where the chosen branch joins a major stem. Work your way around the plant to stagger the branch removal.
Clip off any small shoots around the trunk of the shrub. Also remove any new shoots appearing from the ground next to the shrub.