Why Hydrangeas Don't Bloom
Botanical Names: panicle hydrangea (Hydrangea paniculata), French hydrangea (Hydrangea macrophylla), lacecap hydrangea (Hydrangea macrophylla normalis)
Wondering why your hydrangea is not flowering? Several situations could account for the lack of colorful blooms—some within your control, and some beyond it. Learn what you need to do when hydrangeas aren’t flowering.
Probably the top cause of hydrangeas not flowering is pruning at the wrong time. Both French hydrangeas (Hydrangea macrophylla) and lacecaps (Hydrangea macrophylla normalis) form flower buds during the summer — a whole year before plants bloom. For once-blooming hydrangeas, pruning during late summer, fall or in early spring the following year can remove flower buds.
New repeat-blooming hydrangeas overcome this problem by flowering on both old stems and new growth. With these hydrangea shrubs, even if you prune in early spring, you’ll still get some flowers on the new stems that form. For the strongest flower show, though, you should leave as many stems as possible, both old and new.
Late spring freezes can also result in no flowers on hydrangeas, especially with the once-blooming French and lacecap types. If a late spring freeze kills flower buds that formed the previous summer, you won’t get to savor beautiful blooms this growing season. Repeat blooming types can overcome buds lost to a late freeze because they also form flower buds on new stems.
Another reason gardeners wind up with no flowers on hydrangeas is usually due to sunlight — lack of it. For all but panicle hydrangea (Hydrangea paniculata), the ideal setting for hydrangea shrubs tends toward morning sun and afternoon shade. If plants are tucked into too much shade, few flowers form. French and lacecap hydrangeas need at least three hours of sun to stage astrong flower show.
Too much nitrogen fertilizer can also result in hydrangeas not flowering. When nitrogen fertilizer, especially from lawns, keeps washing into soil around hydrangeas, you can wind up with full plants covered with deep green, healthy leaves, but few flowers. Make sure that lawn fertilizer isn’t landing on hydrangea planting areas.
If none of these conditions apply to you and you still have no flowers on your hydrangea, you may be trying to grow it in too cold of a zone. Some hydrangea shrubs can survive winter in a too-cold zone, but they will never flower because the cold kills the blossom buds. Do some research to determine if your hydrangea shrub is rated to survive in your zone. If it’s not, plant a replacement that is, and get ready for flowers.