For many, hydrangeas are the highlight of their landscaping, growing and blooming in bright displays through the yard. Unlike some of the more exotic plants, hydrangeas are not hard to care for. The primary means of care is an annual pruning. This should be done at different times, depending on the type of hydrangeas you’re growing.
When to Prune Hydrangeas
The best time to prune will depend on the variety of hydrangeas you have. The most common types, called Peegee Hydrangea (H. paniculata Grandiflora), sport massive snowball-shaped flower clusters that bloom in mid to late summer. These begin white and slowly turn pink. This variety thrives with regular pruning, usually done in the late winter or early spring to both shape the plant and encourage new growth.
Bigleaf, Mophead, or Florist Hydrangeas (Hydrangea macrophylla) are also a popular variety thanks to their easily-controlled flower coloring (blue in acid soil, pink in alkaline). These should be pruned as soon as the flowers have faded and before buds have set, usually in early to mid fall.
Another popular variety is the Hills-of-Snow or Sevenbark Hydrangea (H. arborescens Grandiflora). This variety does not overwinter well in colder areas, so it will likely be killed back to the ground in the winter and require no pruning. Winter pruning in warmer areas can be done anytime after the leaves have fallen off the plant. A similar variety, Annabelle, should be treated the same.
Oakleaf Hydrangea (H. quercifolia) is usually grown for its leaves rather than its blooms. Since it blooms only on new growth, this variety can be pruned during the late winter or early spring. This goes for other, similar varieties such as Tea of Heaven (H. serrata).
Climbing Hydrangea, which is a vine rather than a shrub, does not require pruning except to keep it in bounds for shape and size.
How to Prune Hydrangea
In all cases, pruning is the same no matter the hydrangea variety. Once you have established the timing, the rest is dependent on your goals for the pruning. Pruning away dead limbs and foliage should be done no matter how it affects the appearance of the plant, of course. The rest of your helpful pruning will be done to the live portions of the plants.
Most varieties of hydrangeas, with the exception of BigLeaf, Mophead, Florist, and Climbing, blossom and bloom only on new growth. So to encourage new growth and thus a maximum amount of flowering, these plants should be pruned about 1/3 of the way back unless you’re encouraging the whole plant to continue growing for size and volume. In that case, cuts should be made about 3-4 inches back from live ends. This encourages new growth and does little to shrink the size of the plant.
When pruning BigLeaf, Mopehead, or Florist hydrangeas, the cuts should be made at the same measurements, but should shy away from any buds as these overwinter and will be the buds and flowers of the spring.
Hydrangea Pruning Tips
When pruning, cut straight with the snips unless you’re hoping to influence the direction of new growth. Keep your snips sharp so that they cut cleanly rather than crushing the limb or stem. Crushing can cause damage that will prevent new growth. Similarly, the torn or jagged ends from cutting with a knife can be problematic.
Prune your hydrangeas with an eye towards new growth and shape. Most prefer the generally rounded shape that naturally comes to most hydrangeas. Lower branches are the ones that most attention should be paid to for proper shaping.