Evergreen and deciduous shrubs provide borders or focal points in landscapes and come in numerous species, offering a good selection to pick from. Choose from shrubs that maintain color all year long, known as evergreens, or deciduous shrubs that are available with spring and summer blossoms in vivid colors. Most shrubs live for many years when properly maintained. Caring for shrubs requires pruning on a regular basis. However, according to the Iowa State University, "an important aspect of pruning is knowing when to prune plants."
Prune evergreen shrubs early in the season before spring growth emerges, around the end of March or beginning of April. Pruning evergreen shrubs lightly at the end of June or beginning of July is acceptable, but no fall pruning should be done. Pruning deciduous shrubs depends on the time of year the shrubs blossom. Prune spring-flowering shrubs following the bloom period. Prune summer-flowering shrubs and shrubs with no flowers in late winter or the beginning of spring, suggests the Iowa State University.
Make the pruning cuts at an angle, 1/2 inch above an outward-facing bud or back to a lateral branch on the shrub using the proper pruning tool. Use pruning shears for branches up to 1/4 inch, lopper shears for branches with diameters from 1/4 to 1/2 inch and a pruning saw for any branches over 1/2 inch.
Cut away all damaged, weak, dead or diseased branches on evergreen and deciduous shrubs. Prune branches touching or crossing the middle to improve light penetration and air circulation in the shrubs. Remove suckers or shoots growing from branches and shrub stems.
Prune deciduous shrubs one of three ways--thinning out, gradual renewal or rejuvenation pruning. Remove the longest and oldest branches of the shrub by cutting these branches back to the ground, to a lateral branch or to the main stem for thinning out. Prune two or three of these branches back to ground level every season for gradual renewal, and eliminate a third of the deciduous shrub's longest and oldest branches "at or slightly above ground level before new growth starts" for rejuvenation pruning, suggests the Texas AM University.
Prune evergreen shrubs using the thinning method, suggests the University of Arizona. The Texas AM University recommends pruning evergreen shrubs lightly, and to allow the shrubs to form a natural appearance.