If you want to change the color of your hydrangeas to pink here is what you can do. - First test the pH level of your soil. You will need a pH of 6.5 to achieve pink flowers. - To raise the pH of your soil you must make your soil more alkaline. You can achieve this by adding 4 ounces of lime around the base of your hydrangea plant for every point of the pH scale. For example if you have a pH of 4.5 you need to add 2 X 4 ounces of lime. Here is a more technical explanation why hydrangeas change color: http://www.killerplants.com/weird-plants/20020117.asp This is an answer to a question member Seattle Gardens asked