It is important to determine the kind of hydrangea you have to know the ideal time in pruning it. Macrophylla and paniculata are the most common varieties of hydrangeas.
Macrophylla Hydrangeashave big leaves that have flowers that change colors. When you plant it in acidic soil, the flowers become blue. If planted in alkaline soil they become pink. If you prune these in spring, they either hardly bloom or worse will not bloom at all. When you prune the back stems, it is best to use clean and razor-sharp prunes and cut above a group of leaves.
Paniculata hydrangeas grow on new wood. This means that it grows in the same year. Plants that grow on new wood blossoms later than old wood. In pruning these, it is not as critical as the other varieties. However, you need to keep in mind to avoid cutting when the buds are about to open. When these are growing actively, it is recommended not to cut more than one-third whatever the period is.