Thanks to plentiful rain and other friendly conditions, this is the summer of the Hydrangea in the Northeast, at least as far as I’ve observed. Huge stands of paniculata, macrophylla, and arborescens varieties are blooming profusely. My neighbor’s pink macrophylla blooms are easily a foot in circumference; it’s amazing they’re not pulling down the whole shrub. My macrophylla ‘Alpenglow’ doesn’t have huge blooms, but they are profuse and a rich, deep pink (changing now to deep rose-brown).
Inevitably, during Garden Walk, this hydrangea attracts attention and questions. Many visitors seem to think there’s some kind of secret potion I’m pouring into the soil. Gardeners are routinely told by many nurseries that they must adjust the pH of the soil in order to achieve the hydrangea colors they desire. This is something I’ve never done, and all my surviving hydrangeas have remained exactly the same color promised on their labels when I bought them. Either I have the perfect soil for each shrub (seems unlikely) or the predisposition of the hybrids is maintaining consistent bloom color (seems likely).
It’s not color that people should worry about, especially with bigleafs. Many of the gardeners who visit me also complain that they never get blooms. I think this probably has to do more with weather and the natural urge of neatnik gardeners to cut back shrubs every chance they get. With macrophyllas, the buds form in late summer and must survive the winter and—even more dangerous—spring clean-up efforts. Basically, the first rule is do no harm. Some winter protection is often necessary, but that’s all I ever do. (I do prune my paniculata and arborescens in very early spring.)
I went to my favorite source to learn about color change in hydrangeas, the Garden Professors Facebook page, and I found this statement by Linda Chalker-Scott: Genetics plays a large role in color and it’s not necessarily overcome by soil pH. In her article here, it’s clear how complex hydrangea coloration can be. What I got from it is that it might be best to leave such manipulation to the scientists, and buy strong, reliably colored hybrids.
And hope we get another year like this one.