When to Prune Your Woody Shrubs

By Joanne K., Pitt County Arboretum Extension Master Gardener Volunteer

With the approach of spring, gardeners are eager to head outside to get a head start on the multitude of spring chores awaiting them. One of those may include pruning woody shrubs.

Although pruning is not necessary every spring, it's the time of year when bare limbs allow gardeners to see the shape of the plant to determine if winter cold, insects, or disease has caused damage, if the natural growth of the plant needs to be managed, or the ornamental appeal of the shrub could be enhanced. If any of these are true, then it is time to prune.

Abelia x grandiflora 'Kaleidoscope

But a word of caution: be careful to prune at the right time. Otherwise, you will lose or reduce that year's blossoms.

 Chaenomeles Flowering Quince

Shrubs flowering before May should be pruned as soon as possible after blooming. These shrubs include forsythia (Forsythia spp.), hydrangea (Hydrangea arborescens, Hydrangea paniculata), mock orange (Pittosporum tobira), flowering quince (Chaenomeles spp.), spirea (Spiraea spp.), and viburnum (Viburnum spp.). Pruning in late summer, fall, winter, or early spring removes the flower buds formed last summer.

Summer- and fall-flowering shrubs should be pruned before new growth begins in the spring as the buds form on that new wood. These include abelia (Abelia spp.), beautyberry (Callicarpa americana), butterfly bush (Buddleia davidii), crape myrtle (Lagerstroemia indica), gardenia (Gardenia jasminoides), bigleaf hydrangea (Hydrangea macropylla), nandina (Nandina domestica), and Rose of Sharon (Hibiscus syriacus). All of these bloom on new growth in the current season.

Evergreen shrubs usually only need minimal pruning in early spring. These include boxwood (Buxus simpervirens), Japanese aucuba (Aucuba japonica), camellia (Camellia spp.), Japanese hollies (Ilex crenata cultivars), and azaleas (Rhododendron spp.).

Sometimes, overgrown shrubs need more than a few selected cuts. In this case, renewal pruning, which removes the oldest branches of a shrub by cutting them to the ground, leaving younger branches, is required. Although this reduces flowering in the next season, the plant will be

Lagerstroemia indica Crape Myrtle

healthier in the long run. Shrubs responding well to such pruning include azaleas (Rhododendron spp.), butterfly bush (Buddleia davidii), forsythia (Forsythia spp.), hollies (Ilex spp.), mock orange (Pittosporum tobira), spirea (Spirea spp.), and weigela (Weigela florida).

There is no need to treat pruning cuts with sealers, as doing so may slow healing. Avoid pruning after July 4 because the new growth may not mature before cold weather sets in and this could damage the plant. The exception is dead, diseased, damaged, or crossing limbs, which can be removed at any time.

Pruning shrubs is both an art and a science. Your shrubs will thank you when you do it right by following the above practices at the right time.

All photos: J. Kollar
1. Abelia x grandiflora 'Kaleidoscope 
2.  Chaenomeles Flowering Quince
3. Lagerstroemia indica Crape Myrtle