In The Garden: Why Didn’t My Hydrangeas Bloom This Year?
Every year, at least one client asks me this question. As with any living thing in nature, the question “why?” often has several answers that could apply. Here are some of the reasons why hydrangeas don’t bloom…
Usually the Problem is Poor Trimming Practices
Some hydrangeas bloom off “old wood”, meaning last year’s branches. These hydrangeas include the old fashioned Big- leaf and Lacecap types (Hydrangea macrophylla), and the Oakleaf hydrangea (H. quercifolia).
Old wood hydrangeas begin to set buds with the first frost, so in Middle Tennessee this is usually in October. It is very important to get your trimming schedule right! Trim them after they bloom but before they set bud in about October. If you trim them after frost, you are pruning off next year’s blossoms. And remember, the more old wood you trim off, the fewer blooms you will have.
“New wood” hydrangeas like Annabelle (H. arborescence) and peegee types like Limelight and Tardiva (H. paniculata) are much easier to get right. Pruning them back any time before spring will inspire them to produce new growth. The more new growth, the more summer blooms you will have. It is easy to grow these hydrangeas because they should bloom no matter how you prune them.
A modern cultivar, the Endless Summer series, blooms off old wood in early spring and then again off new wood later in summer. That is why they bloom all summer! These are practically fool proof.
The important thing about success with hydrangeas is to correctly identify which kind of hydrangea you have, so you know when to trim them.
So if you have pruned your hydrangeas in a timely manner, that means they should bloom without any problem, right? Not necessarily…..
Extreme Weather Can Affect Bud Formation
If conditions are too dry during the time when the plant is trying to form buds, the buds may not form. If Nashville has an extremely cold winter, buds can be damaged. If buds get caught in a late spring freeze after they have come out of hibernation, they are especially fragile and can be damaged. Damaged buds may not bloom the following summer.
Too Much Shade
Hydrangeas are popular because they are one of the few shrubs that bloom profusely in shady areas. However, even shade-loving hydrangeas need some sun to bloom well. Endless Summer and Oakleafs especially love direct morning sun with afternoon shade, or all-day dappled light.
Annabelles, Limelights, and Tardiva can take all day sun, but still benefit from some shade during the hot late afternoon. If your hydrangea is in deep shade and is not blooming, you may need to move it (or trim your trees) for a better response.
Hydrangeas are great additions to the landscape and are often trouble free. Knowing when to prune them and where to plant them may solve the mystery of why they don’t bloom. Sometimes we just don’t know for sure because nature doesn’t always explain itself. — By Ann Jackson
Editor’s Note: Ann Jackson is director of sales, marketing, and creative interpretation for Turf Managers, LLC. in Nashville. An avid gardener, Ann is also a certified lawn and horticultural professional through the Tennessee Department of Agriculture, and provides design services for commercial and residential landscapes and flower beds. E-mail your questions to her at firstname.lastname@example.org.