Hydrangeas should be trimmed annually, or when they grow excessively large for a given space. Varieties such as Pee Gee and smooth hydrangeas blossom better from new stalks than from older and more established woody stems, and they can be trimmed in winter or early spring without harming the plant.Continue Reading
Big leaf and mophead hydrangea varieties bloom better on old stem growth and should be pruned immediately after flowering in the summer.
Some varieties of big leaf hydrangeas, such as the Endless Summer hydrangeas, have been hybridized to flourish on new or old stems. This allows for a greater degree of flexibility when pruning the flower.Learn more about Outdoor Plants & Flowers