Time to Prune Hydrangeas?

— Written By and last updated by white hydrangea Blue Hydrangea

Hydrangeas that bloom on “old wood”

Hydrangeas are a bold, bright, and beautiful way to add color and texture to your landscape. With immense, striking flower heads that are unrivaled in the shrub world, hydrangeas are hard to resist. Hydrangeas are easy to cultivate and propagate, tolerate most soils, and produce abundant blooms that provide several weeks or even months of eye-popping color. They come in a wide range in colors, including bright white, frosty white, vibrant blues and pinks, lavender, rose, and even lime green. 

Pruning hydrangeas can be confusing. Proper timing and knowing which pruning techniques to employ depend on the variety. The BigLeaf (H. macrophylla), along with Oakleaf (H. quercifolia), Mountain (H. serrata), and Climbing (H.anomala subsp. petiolaris) hydrangeas are among the most popular varieties. They all bloom on the previous season’s stems (“old wood”).

After the above varieties bloom, usually in June and July, it is time to prune. Avoid pruning after August 1, because the flower buds for next year’s blooms form in late summer. To encourage branching and fullness, cut one or two of the oldest stems down to the base. If plants become old, neglected, or damaged, prune the entire plant down to the base. You will lose the flowers for the upcoming season, but also rejuvenate the plant for years to come. 

For the best results when pruning the big Mophead varieties, do not deadhead or remove the faded blooms. Leave them through the winter and cut them back in early spring (to the first pair of healthy buds). Lacecap varieties can be deadheaded. Cut them back to the second pair of leaves below the flower head. For more detailed information about pruning hydrangeas, check out this link to an article written by Extension Director in Macon County, Alan Durden: Pruning Hydrangeas

Hydrangeas that bloom on “new wood”

Panicle (H. paniculata) and Smooth (H. arborescens) hydrangea varieties bloom on the current season’s stems or “new wood”. These varieties should be pruned in late winter BEFORE the flower buds form. Given ample space to grow, these varieties require considerably less maintenance. Typically, prune out the dead branches only, and do not try to “shape” this shrub.  

Hydrangea Variety When to Prune Where Blooms Appear
Panicle (H. paniculata) Late winter, before spring growth On new growth
Smooth (H. arborescens) Late winter, before spring growth On new growth
Bigleaf (H. macrophylla) Summer, after flowering On old growth
Oakleaf (H. quercifolia) Summer, after flowering On old growth
Mountain (H. serrata) Summer, after flowering On old growth
Climbing (H. anomala subsp. petiolaris) Summer, after flowering On old growth

If you have additional questions about this topic or any other horticulture-related topics please contact Chris Blaha at  252-232-2262 or email ctblaha@ncsu.edu