Hydrangea: Failure to bloom

Biology

Improper pruning is the most common reason hydrangeas fail to bloom. Both bigleaf (Hydrangea macrophylla) and oakleaf (H. quercifolia) hydrangeas produce their flowers on the previous year’s growth. If these stems are removed, new growth may fail to produce flowers that season. Panicle (H. paniculata) and smooth (H. arborescens) hydrangeas flower on current-season growth, so heavy summer pruning of these species can reduce flowering. Bigleaf hydrangeas may also fail to bloom due to environmental conditions. Freezing temperatures early in the fall before the plant is completely dormant, late-season spring frosts, and very cold winter temperatures can damage or kill developing flower buds. Plants which are placed in very shady locations may not bloom as profusely as those that receive more light.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Choose the proper planting site. Most hydrangeas prefer morning sun and some light shade during the hottest part of the day. Do not place in locations susceptible to very early or very late frosts.
• When necessary, prune in winter or very early spring, before buds begin to swell. Remove up to 1/3 of the oldest growth, including thin, weak, or damaged stems.
• Removing old flower heads after flowering is completed will help control height and improve appearance of the plant.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• None recommended