Knowledgebase
Hydrangeas that won't bloom. #757458
Asked June 21, 2021, 12:36 PM EDT
Does anyone know anything about hydrangeas? I have 5 bushes I planted around our deck over the last 4 years and none of them will flower any longer. This is the second year in a row that I have had not one flower. In 2019 I got one flower! I used bone marrow once last year and once this spring, plant food this year, bloom booster last year, and no results. They are old wood growers so I do not prune them. I had them at our old house and never did a thing and had flowers galore. They are planted on the east side of the house but we live adjacent to 18 acres of woods so they get morning sun but only dappled in the afternoon if any as the trees are too full. Any experts out there?
Thank you in advance for any information.
Clinton County Michigan
Expert Response
You did not mention the variety of hydrangeas you have. If you purchased them from a garden center, were they appropriate for your hardiness zone? This article from the University of Massachusetts Amherst has some particularly good information on why hydrangeas do not flower. The link is located here: Landscape: Why Hydranagea macrophylla Don’t Flower | UMass Center for Agriculture, Food and the Environment
Some newer varieties, which came to market around 2004- most notably "Endless Summer" were bred to have the ability to bloom not just on wood made the previous year, but also on new wood. If this is what you have, hopefully, you may get some bloom later in the season. Here is our guide to pruning hydrangeas Guide to Pruning Hydrangeas | University of Maryland Extension (umd.edu)
Cold damage - This type of hydrangea blooms on old wood so a cold winter or the springs late frosts or freezes may have killed any buds present. Once plants break dormancy, they lose the ability to tolerate frost. Again, if you have a newer variety, it may bloom later this season.
Do not overfertilize as this will promote lush foliage at the expense of flowering. More on why trees and shrubs failure to flower Trees and Shrubs Failing to Flower | University of Maryland Extension (umd.edu)
Thank you for your question and I hope you have a great gardening season.
Thank you for contacting me. I am out of the office for summer vacation and will not be returning until Tuesday, August 24th, 2021.
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