Summer blooming Spireas should be pruned in late March or early April
Late March and April in CT means it is time to start pruning the flowering shrubs in your yard that bloom on new wood. What does that mean? There are two categories of shrubs. Those that bloom on last year's wood already have their flower buds set on the branches. If you were to prune them now, you would cut off this year's flowers! Shrubs that bloom on NEW wood should be pruned now. They will start to grow and produce lots of fresh, healthy, young new wood (also called current year's wood) which will give you lots of flowers in the summer and fall.
Prune these shrubs in April
Abelia grandiflora- glossy Abelia
Baccharis halmifolia- saltbush
Buddleia davidii- butterfly bush
This is one of my butterfly bushes in early April after pruning. They can be cut very hard. You can even cut them to the ground if you want to keep them small.
Be brave! Cut your purple beautyberry bushes hard!
Caryopteris clandonensis-blue mist shrub
Cornus-colorful twig types
This is the after picture after I did a hard pruning on my red twig dogwood in late March. If you don't remove a lot of the old wood, you lose the fresh, young, red twigs.
Heptacodium miconiodes- seven sons tree
Hibiscus syriacus-rose of Sharon
Hydrangea arborescens- smooth hydrangea
My Hydrangea arborescens before pruning in late March (above) and after pruning (below).
Hydrangea paniculata-panicle hydrangea
On the left is Hypericum 'Hidecote' in bloom in the summer. On the right is what it looks like in March. Cut it to the ground!
Above is my Potentilla shrub in June. Below on the left is what it looked like before pruning. On the right is after pruning. I do this again in mid-July to get a better second bloom season in late summer.