What shrubs should you prune in the spring? The rule of thumb is that in the spring you prune shrubs that bloom on current year's (new) wood. This category of shrubs are summer blooming.
What does current year's wood mean? All shrubs are broken down into two categories:
1. Plants that bloom on last year's or OLD wood are late winter and spring bloomers. Their flower buds are set up the year before, usually 4-6 weeks after the plant has finished flowering, and the buds are already on the plant through the winter and when early spring arrives. Those plants are pruned immediately after blooming. If you prune them in the early spring, you will cut off all the buds!
2. Plants that bloom on this year's wood or NEW wood are summer bloomers. Their buds are set up in late spring and early summer and then the plants flower. The time to prune them is in late winter and early spring, just as they are breaking dormancy. In CT, that work is usually done in April.
Buttonbushes bloom in late summer on current year's (new wood) and should be pruned in the spring
The goal in pruning these plants is to cut back the old wood and encourage lots and lots of new growth which will mean you will have lots and lots of flowers. At the same time, you should remove any dead wood and, in many cases, remove some of the older wood from the center to allow room for new shoots to grow.
This is a list of plants that grow in CT that bloom on current year's (new wood) that you should prune in April.
Abelia grandiflora (glossy Abelia)
Baccharis halmifolia (salt bush)
Buddleia (butterfly bush)
Glossy Abelia blooms from July thru late September on new wood and should be pruned in the spring.
Caryopteris (blue mist shrub)
Cephalanthus occidentalis (buttonbush)
Heptacodium miconioides (seven sons tree)
Hibiscus syriacus (rose of Sharon)
Hydrangea paniculata (panicle hydrangea) and Hydrangea arborescens (smooth hydrangea)
For information on how to prune all species of hydrangeas, download our hydrangea handout from our website at www.naturework.com
Hypericum (St. Johnswort)
St. Johnswort blooms in the summer on new wood and should be pruned hard in the spring
Lagerstroemia (crape myrtle)
Leptodermis oblonga (Chinese Leptodermis)
Lespedeza (bush clover)
Potentilla fruticosa (bush cinquefoil)
*Note: there are many different types of roses. For more detailed information, download our rose handout from our website www.naturework.com
Spirea -summer blooming types such as 'Neon Flash', 'Anthony Waterer', 'Gold Mound', 'Double Play' series, 'Shirobana' .
*Note that spring blooming spireas such as S. x vanhouteii and S. prunifolia (bridal wreath types) bloom in spring on old wood and are pruned after blooming.
Vitex (chaste berry)
Vitex blooms in July and August on new wood and is pruned in the spring.
Here are a few pictures of some shrubs that bloom on new wood and are pruned in the spring:
Above is a Callicarpa (beautyberry) after it was cut back in April at Natureworks
Below on the left is a Potentilla before pruning. On the right is the same Potentilla after pruning.