I have an endless summer hydrangea that I planted at the beginning of this season. The plant is healthy and starting to bloom, but despite the best of my efforts to the contrary, the flowers are bright pink instead of purple. I used JR Peters acid fertiliser several times while the plant was taking root and initially growing, and most recently as the plant has matured, I've used Espoma Organic soil acidifier. The plant is in sandy soil and the surface is covered with cedar mulch. Am I doing something wron in my efforts to turn this plant's flowers purple???
Oakland County Michigan
Thanks for your question regarding hydrangeas. Here’s an Extension article about these plants that explains how changing the soil acidity may be able to do that: Typically, the more common macrophylla (moptop) is easiest to impact. There is a possibility you have a hydrangea that simply won’t change the color. Be sure to follow instructions when adding the acid fertilizer.