hydrangeas color changing
I purchased a blue endless summer hydrangea last year and had the most beautiful blue flowers. During the season last year it started to bloom pink flowers. I purchased alum. sulfate and added 1T with a gallon of water this year in the spring and 1T with water in July. I have two blooms that are starting which are now pink. How often and how much should I added alum. sulfate to change it to blue?