Shrub pruning is necessary to keep plants healthy and orderly. It allows the gardener to control the growth of the shrub, as well as reducing the chance of disease and encouraging new limbs and flowers to form. Many gardeners only prune away dead branches, but it is equally important to trim back excessively long or diseased limbs. The two basic ways to cut the branch are heading and thinning. Both cuts are effective, but each will manipulate the plant into growing in different ways.
Use the heading cut to stimulate the growth of buds nearest the wound, or the point where the branch is cut. Heading cuts are made against the direction the branch is growing. This cut makes the foliage on the branch considerably thicker, but is generally considered less attractive, making it the less commonly used method in shrub pruning. New growth also forms on the location of the cut, essentially regrowing the limb. Heading cuts should never be made at the point where the branch originates from the shrub.
Use thinning cuts to form a compact branch structure and remove dead or diseased limbs when shrub pruning. Thinning cuts do not stimulate regrowth at the site of the wound, but instead encourage other offshoots to grow. Thinning cuts are always made at the branches' point of origin, and in the same direction as the growth of the branch. Both thinning and heading cuts should be made at a 45 degree angle to prevent rot and promote growth.
Deadheading is the process of removing dead or wilted flowers from the shrub. It is important to redirect nutrients from the dead flowers to the root and branches, stimulating growth. Dead flowers are also unattractive, and removing them improves the overall look of the shrub. Perform deadheading immediately after the flower dies to promote optimal growth. Remove only the dead flower, and take care not to cut away any live portions of the tree.
Remove any branch from the shrub that is dead, diseased or damaged. These branches only cause further harm to the shrub, and removing them stimulates the growth of roots, foliage and new branches. Prune diseased branches quickly and as close to the point of origin as possible to prevent further spread of disease.
Prepare a bucket filled with soapy water prior to shrub pruning. After each cut, dip the pruning shears into the water to kill any diseases or pests that may have infected the shears. This prevents the spread of these ailments to other portions of the shrub. It is a good idea to burn all diseased branches at a remote location so any fungal spores will not spread.
Perform shrub pruning on flowering plants immediately after the blossoms have faded. This will allow the shrub to focus on the growth of foliage and branches, rather than seeds or fruit. Pruning during other times may stunt the growth of the shrub, and result in less flowers the following blooming season. Shrubs under one year old should never be pruned.