When to Cut Shrubs

Flowering Shrubs

• Old wood is wood that was produced the year before while new wood is growth produced during the current growing season. Gardeners need to know whether their flowering shrub flowers on old wood or new wood. Flowering quince, for instance, flowers in early spring. Most flowering hedges that flower in early spring bloom off old wood. Flowering shrubs that flower in summer, like mimosa and crape myrtle, bloom on new wood -- branches that grew only a few weeks before the flowers. Late spring bloomers are pruned in early spring, before new growth begins. Early spring bloomers are pruned in late spring, after flowers have faded and fallen.

Shaping

• Cut shrubs when they are young in order to train them into appropriate mature shapes. To make treelike shrubbery, choose a leader branch during your shrub's first year. Train this leader as you would a tree trunk, establishing lateral branches and trimming back bottom limbs to establish a treelike shape. For traditional, formal hedges, bushes are trimmed so that top branches are smaller than bottom branches. This builds a stable base and allows light penetration from top levels to bottom branches. For natural shaped shrubs, follow the shrub's growth pattern. Trim back unwieldy branches and avoid shearing tops and sides. Instead, cut back crossed branches and head back all branches to varying lengths. This results in a more natural appearance.

Renewal Pruning

• Homeowners with overgrown bushes and hedges cut back their hedges in early spring. This kind of pruning is usually severe and not all bushes can withstand this kind of intense cutting back. Broad-leaved shrubs like azaleas and privets are able to tolerate these cuts, but narrow-leaved evergreen shrubs like cypress and pine should be transplanted once they have outgrown their site. They will not be able to recuperate from renewal pruning. Renewal pruning occurs when gardeners cut back all branches to within 6 to 12 inches of ground level. Early spring is the best time because new growth won't encounter frost damage. New growth is trimmed and shaped throughout the growing season to train and maintain a compact shape.

Extended Renewal Pruning

• Extended renewal pruning follows the same process and timing as renewal pruning, but instead of cutting back all branches in a single season, one-third of the branches are cut back each early spring. This process takes three years but allows a plant time to recover.