The flowering shrubs in your landscape can provide enjoyment all season. However, there are a few things to keep in mind when pruning so you enhance their flower production.
Pruning Spring Flowering Shrubs
Spring flowering shrubs are defined as those that produce flowers any time 
from early March to late May. They either produce their flowers before the new leaves emerge, or shortly thereafter. Examples of these shrubs include magnolia, azalea, and lilac. To produce flowers in the spring, these shrubs create their flower buds during the summer and fall of the previous year. If you prune them in th fall, you will remove the flowers that they are creating for the next spring. The correct time to prune these shrubs is shortly after they bloom in the spring so they have time to create their new flower buds during the summer.
Pruning Summer and Fall Flowering Shrubs
Pruning summer and fall flowering shrubs is more flexible. These shrubs are defined as those that produce their new growth during the spring and, as they are growing, generate flower buds. Examples of these shrubs are hydrangea, roses, and butterfly bush. These shrubs can be pruned in early 
spring before they are starting their new growth, or at the end of the growing season in your area. For shrubs like roses that produce flowers in spurts all summer, you can trim them when the current wave of flowers is dying. In fact, to produce more flowers on roses, it is a good idea to cut off the dying flowers so the plants use their energy to produce more blooms.
General Pruning Tips
For most plants, it is better to trim them when they are in an active growth phase. This enables them to recover quickly from the “damage” caused by trimming. Don’t prune your shrubs during periods of hot, dry weather. They are likely under stress from the head and lack of rain, and the act of pruning will provide the opportunity for insects and disease to infect the plant. If you are unsure of when and how to prune, consult a trusted garden center for advice on your individual situation.
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