vanilla strawberry hydrangeas
I planted multiple hydrangeas 2016 - Bobo, limelight, and several “vanilla strawberry” that are supposed to turn from white to pink. The Bobo and limelight are doing fine. But sadly, the vanilla strawberry variety have never turned pink - they just go from white to green. I was hoping that it would just be a matter of time for them to become established but am getting worried they just won’t perform in our conditions. My soil is very moist and slightly alkaline - I’ve read that ph doesn’t affect the color of these hydrangeas but am wondering if I should try to apply soil acidifier or if there is anything else I can try.
You are correct that soil pH doesn't affect the color of the 'Vanilla Strawberry' panicle hydrangea. Based on your description of the flowers turning from white to green, we wonder if the plants were mislabeled. Unfortunately, that happens sometimes in the nurseries. We talked to a landscaper who specializes in hydrangeas and he noted that the pink types like 'Vanilla Strawberry' have not had very good color this year, which suggests the weather may have an influence. These like sunny and drier weather. Are yours located in full sun?
If it is any consolation, I put in a new 'Strawberry Sundae' variety this year and it has remained white with no signs of pink. I thought it might have to do with the maturity of the shrub -- it is still getting established -- and the wet weather has been tough on it this season.
We cannot think of anything specific to try. If you have the plant in a full sun location and the plant appears to be healthy otherwise, wait and see if they do better next year.