02 Oct Why Didn’t My Hydrangeas Bloom this Year and What Can I Do About it???
Last Saturday, I packed the teaching tent with over 25 people all wanting to learn about hydrangeas. The top question on everyone’s mind was “why didn’t my hydrangeas bloom?”.
Hydrangeas in the spring. After a warmer winter, the one year old wood is alive and there are viable buds emerging.
Last winter we had severely cold temperatures, colder than I have seen in decades, when we dropped to minus 12 degrees below zero for nearly a week. This froze the blooming wood on most old fashioned pink and blue Hydrangea macrophylla varieties. This species bloom on ONE YEAR OLD WOOD. Unfortunately, this wood is only hardy to zone 6 and 12 degrees below zero is much too cold. Simply stated, last year’s canes died. Gardeners left the “sticks” up for the entire spring, hoping in vain for signs of life. Instead, fresh, green growth sprung up from the roots (which are MUCH hardier, to zone 5). Because the old varieties of pink and blue hydrangeas only flower on one year old wood, this current year’s growth did not produce any blossoms.
You have two choices to solve this problem. Last week I finally ripped out an old hydrangea that I inherited with my house 10 years ago that has NEVER flowered for me. I will be replacing it with a modern cultivar, ‘Bloomstruck’, that blooms on old AND new wood. The second choice is to protect your older varieties. After the leaves fall off, do NOT cut down the canes. Instead, spray them with Wilt-pruf, an antidessicant spray made of pine sap. Then, pound sturdy stakes into the ground and staple gun burlap to the stakes. This will protect the canes from strong winter winds.
We have a comprehensive Hydrangea handout available that describes the different species and how to prune and care for them, click here.