You can stick a pencil or your finger in the soil by the hydrangea and see if it is too wet or dry. Another way to tell is if the soil is mushy and smells stinky. If so, you need to do something about the drainage and soil preparation. Endless Summer has a planting and care guide with tips for growing healthy hydrangeas. I bet it will help.
Question
AM I OVERWATERING OR UNDERWATERING MY HYDRANGEAS?
Answer
Sometimes, it is hard to tell if there is too much or not enough water. However, the answer is in the dirt.
