Summer flowering shrubs illuminate the garden with their bright colors throughout the summer and sometimes until the first frost. To take full advantage of their beauty, a few pruning steps must be taken.
The right time to prune
The majority of summer flowering shrubs have the particularity of flowering on the year's branches. Pruning at the end of winter will be beneficial because it encourages branching and the emission of new shoots that will then flower abundantly in summer. To make this possible, pruning should not be too late as it would compromise or delay flowering. The best time to prune these shrubs is in February or March, outside of the frost period, before vegetation starts to grow again on deciduous species.
How to prune summer flowering shrubs?
Protect yourself with gloves and use pruning shears and a lopper if the shrubs have branches with a larger diameter.
Training pruning
On young and newly planted shrubs, a so-called "training" pruning may be necessary. It stimulates the growth of the plant while giving it a harmonious shape. It consists in reducing the stems by half by pruning above an outward facing eye or to put in place the carpenter branches. Indeed, keeping a low framework on certain shrubs will allow to make a maintenance pruning much lighter in order to keep the volume of the plant. A common trunk will then carry 5 to 6 carpenters which will each divide into 2 or 3 branches. Young baguenaudier, deciduous ceanothus, Hydrangea paniculata or arborescens, Spanish broom or summer tamarisk are concerned by this pruning.
Maintenance pruning
This is the most frequent pruning which allows to stimulate the departure of new flower-bearing shoots. It consists of removing all dead, diseased or damaged branches at the base of the shrub and also clearing the center of the shrub in order to bring in a maximum of light. The shrub is then aerated, the light rays penetrate in its center and a good air circulation is maintained. Pests and diseases will be less frequent on a pruned shrub.
To finish your maintenance pruning, cut the ends of the branches for a few centimeters always above a bud turned towards the outside, in order to give an aesthetic shape to the shrub and to stimulate the growth of new shoots which will bloom as soon as the summer. At the same time, cut off the branches that flowered the previous year. This pruning can be done on most summer flowering shrubs such as Buddleia, ceanothea, hibiscus, perovskia, summer spirea, caryopteris, lavatera or altheas.
Rejuvenation pruning
This is done on aging shrubs that bloom less and less or on very weak subjects that are still growing despite optimal care.
This pruning consists in cutting the stems at 20 or 30 cm from the ground. Caryopteris, rustic fuschia, Leycesteria, Lespedeza, shrub sage, but also Perovskia can be pruned this way.
