This has always been a big question…and not easily answered! It all depends on what type of this beautiful shrub you have growing in your garden. The different hydrangeas need pruning at different times so it’s important to know which variety you have. If you prune your hydrangea at the wrong time, you may affect its bloom for the season. Other reasons for a non-blooming season could be an early frost, a cold spell, or that it was planted in an unsuitable location.
If you don’t know which variety you have, by looking at the flowers and leaves you can do your best to make an educated guess. The descriptions below hopefully will help! The best chance for a beautiful blooming season is by good pruning!
Bigleaf Hydrangea – Hydrangea macrophylla (photo above)
Bigleaf hydrangeas are the species of hydrangeas that are affected by the pH in the soil. When you see those pretty blue flowers, the soil is acidic; pink flowers, the soil is alkaline. There are a few varieties whose flowers are white, so that makes it a little more difficult to identify them. The leaves on the bigleaf hydrangeas are glossy, dark green and coarsely serrated.
The bigleaf hydrangeas flower in the summer. They should be pruned after their flowers are spent, late summer into early fall, before their new buds have formed. At the same time, pruning some of the old, weaker stems will help to keep your shrub healthy and vigorous.
Peegee Hydrangea – Hydrangea paniculata
Peegee hydrangeas are probably the most common of all of the hydrangeas. (This variety includes tree hydrangea.) They have very large round flowers that start out white in color and slowly turn to pink. Long after the leaves have fallen off the shrub, the flowers persist on the shrub in a dried state.
The peegee hydrangeas flower in the summer but their buds have only formed that spring on new growth. You can prune gently in the late winter or early spring before the buds have formed to remove the old flower heads, groom your shrub and to encourage new growth and hopefully more flower buds.
Annabelle Hydrangea – Hydrangea arborescens
Annabelle hydrangea and its varieties have large white flowers. Its green leaves are somewhat rounded with a pointed end and whose underside is a paler color.
These hydrangeas also flower in the summer on new growth that is formed in the spring so pruning as described above will benefit these shrubs as well.
Oakleaf Hydrangea – Hydrangea quercifolia
Oakleaf hydrangea is very different than the other hydrangeas by both its flower shape and leaf shape. The beautiful white flowers are conical is shape but the oakleaf-shaped leaves are its most treasured feature. An added bonus is the beautiful crimson color of the fall foliage.
Oakleaf hydrangea is another variety that blooms on new growth so a gentle pruning in late winter or early spring will provide what it requires for a wonderful blooming season.
Climbing Hydrangea – Hydrangea anomala petiolaris
Climbing hydrangea is actually a vine, not a shrub, and so does not follow the same regimen that the shrubs follow. Once established, it is very hardy and may only require an occasional pruning to provide you with a season of wonderful flowers!