Most summer-flowering shrubs (blooming after mid-June) should be pruned while dormant in late winter or early spring. The exception is the blue or pink ‘snowball’-type Hydrangea (Hydrangea macrophylla). These Hydrangeas bloom on last fall’s growth, which is why they sometimes do not bloom after a severe winter. The exceptions to that rule are some of the new varieties of Hydrangea that have been bred to bloom on the current season’s growth, such as ‘Endless Summer’ or ‘Penny Mac’.
The following shrubs, in addition to thinning or removing dead branches, may be cut back within 12 – 18 inches of the ground if needed.
Abelia (Glossy Abelia)
Aesculus (Bottlebrush Buckeye)
*Buddleia (Butterfly Bush)
*Ceanothus (New Jersey Tea)
Hibiscus syriacus (Rose of Sharon)
*Hydrangea arborescens (Annabelle Hydrangea)
*Hydrangea paniculata (Pee Gee Hydrangea)
Hypericum (St. John’s Wort)
*Lespedeza (Bush Clover)
*Spiraea bumalda (Spirea)
Spiraea japonica (Japanese Spirea)
*Vitex (Chaste tree)
*should be cut back severely each year