Why Prune?  Pruning is the intentional removal of plant parts and if you do not have a good reason for pruning or do not know why you are pruning, then do not prune!  In Arizona, needs for pruning vary from no pruning to seasonal pruning depending on plant species, location in the landscape and/or intended use.  Pruning should only be done when necessary and at the right time of year. 

Rule #1:  Don’t prune, but if you must, remember that most if not all flowering shrubs look best and flower best when allowed to grow in their natural form or habit.  Shearing is the worst technique to use on flowering shrubs. Examples of shrubs that require little or no regular pruning include Buddleia, Dodonea, Larrea, Ruellia, Simmondsia, Justicia.

Rule #2: Prune spring flowering shrubs after they flower. Spring flowering shrubs bloom between February and the first of June. These shrubs bloom from bud formation on wood produced the previous growing season.  If you remove the buds in late winter, early spring, you will be removing the flowers!  Examples of spring flowering shrubs are Senna, Rosmarinus, Eremophila, Encelia, Euphorbia, Carissa, Calliandra, Oleander, Feijoa.

Rule #3:  Prune summer flowering shrubs in late winter or early spring to promote vigorous growth and flowering in late spring and early summer.  Sumer-flowering shrubs bloom from buds that develop on new wood that grows in spring of the current year.  Frost-damaged plants such as Bougainvillea and Tecoma should be cut back to living wood.  Examples of summer flowering shrubs are Caesalpinia, Leucophyllum, Bougainvillea, Salvia, Justicia, Lantana, Tecoma, Fulva, Thevetia.

Rule #4:  Never shear flowering plants!  Flowers are produced at the tips of the branches or just behind the growing points and shearing removes flower buds, flowers and destroys the natural form of the shrubs.  Shearing is labor intensive and requires repeat shearing to maintain the shape which is typically unnatural looking.

Knowing and understanding the principles behind pruning flowering shrubs results in colorful landscapes year-round.

Article Provided by: COHORT Cindy Odgers, Horticulturist