As the weather warms and buds swell on the shrubs, it’s the right time to prune! Here in central Indiana, early spring (mid-March to early April) is the best time for pruning shrubs that bloom in summer. But don’t take your pruners to spring-blooming shrubs, like lilac, forsythia, and viburnum; those should be pruned right after they bloom.
Pruning your summer bloomers
Most plants that bloom in summer bloom on new wood, which means the current season’s growth. So even if you cut away branches, you won’t be reducing the amount of blooms that you get this year.
According to Purdue University Cooperative Extension Service, these are summer bloomers you should prune in early spring—but only if they need it.
Summer bloomers to prune selectively in spring
- Abelia x grandiflora (Glossy Abelia)
- Cotoneaster spp. (Cotoneaster)
- Hydrangea paniculata ‘Grandiflora’ (Pee Gee Hydrangea)
- Hypericum spp. (St. John’s Wort)
- Mahonia aquifolium (Oregon Grape Holly)
- Rhus aromatica (Fragrant Sumac)
- Rosa cvs. (Hybrid Tea Rose cultivars)
- Sorbaria spp. (False Spirea)
- Stewartia spp. (Stewartia)
- Symphoricarpos spp. (Snowberry or coralberry)
- Weigela spp. (Wigelia)
Cut them back (way back)
While all of the plants listed above may be selectively pruned, we find some do best when cut to the ground each spring. Take out your loppers or pruners, and cut these shrubs to within about 6″ to 12″ from the ground.
Summer bloomers to cut to the ground in spring (wait until early April)
- Buddleia davidii (Butterfly Bush)
- Callicarpa spp. (Beautyberry)
- Caryopteris spp. (Blue-mist Shrub)
- Hibiscus syriacus (Rose of Sharon)
- Hydrangea arborescens (Smooth-leaf Hydrangea)
- Symphoricarpos albus (Snowberry)
- Spiraea japonica (Japanese spirea)
Red- and yellow-twig dogwood (Cornus spp.) have the best color on new growth. So either cut these to the ground each spring OR cut one-third to one-half of the stems to the ground.
Leave spring bloomers alone!
These common spring bloomers should be pruned after they bloom, so hold off until they’re done with their spring show—usually in May or June. (For a complete list of those you should prune after they bloom, see this Purdue publication.)
Spring bloomers to prune in late spring
- Amelanchier spp. (Serviceberry)
- Berberis spp. (Barberry)
- Chaenomeles spp. (Flowering Quince)
- Deutzia spp. (Deutzia)
- Forsythia spp. (Forsythia)
- Philadelphus spp. (Mock Orange)
- Syringa spp. (Lilac)
- Viburnum spp. (Viburnums)
- Wisteria spp. (Wisteria)