When choosing a spot to plant your hydrangea, keep in mind that most hydrangea plants will grow to between 4 and 6 feet in height and width. Plant them in an area where they can grow to their full size without needing to be pruned. Unlike most shrubs, hydrangeas don’t require pruning and they don’t necessarily need to be pruned to flower well. In fact, improper pruning can lead to poor flowering the next year. Removing older stems, however, can help the plant generate new growth. The varieties of hydrangeas are pruned differently, so first identify your species of hydrangea.
Difficulty: Moderately Easy
Bigleaf hydrangeas bloom on old wood.
Remove stray or straggly stems at the soil line. To maintain a neat appearance, snip these stems any time. Plants that bloom on old wood include bigleaf hydrangeas (H. macrophylla) and oakleaf hydrangeas (H. quercifolia).
Snip old blooms just below the flower head.
Cut any other stems around June or July, and before August. Any major pruning you want to do should be done just after flowering, and before new buds are set for the next year.
Do not cut these hydrangeas down to the ground in the winter. By doing so, you will be removing all new buds.
Remove older stems on plants that are more than 5 years old, effectively removing about one-third of the stems. Cut the stems down to the ground to help invigorate the plant and promote new growth.
Smooth hydrangeas bloom on new wood.
Trim crossing branches, branches that stray or any branch that seems "out of place" in the overall shape and form of the shrub. Plants that bloom on new wood include Pee Gee hydrangeas (H. paniculata) and Annabelle hydrangeas (H. arborescens).
Prune flowers any time after they’ve appeared. Some varieties of Annabelles will produce a second round of flowers if they’ve been pruned lightly after their first flowering.
Cut back stems in the late fall or winter. Pruning is not necessary for these plants, but cutting them back in the winter may make your winter landscape more attractive.
Prune stems to the ground for bigger flowers in the spring, and for less visibility in the winter.
Leave old growth at a height of 18 to 24 inches high when cutting back to promote stronger, thicker stems that will be able to hold up large flowers in the spring. Flowers that easily flop to the ground after rains can benefit from this type of pruning.
Remove dead stems from the plant every year as a part of the plant’s maintenance.
Remove old blooms at any time. In August, cut them with shorter stems, so as not to disturb emerging buds. Flowers cut for arrangements in June or July can have longer stems.
Pruning hydrangeas is most important on plants more than 5 years old. Pruning younger plants may harm them.
Whenever you prune, be sure not to cut off emerging buds.