The Hydrangea or Hydrangea arborescens is a beautiful native shrub. The flowers from the Hydrangea form in large bundles that can be as big as 10 inches in diameter. Hydrangeas do better in medium sun and like a lot of water.
The flowers bloom throughout the summer. Depending on the variety of Hyrdangea the flowers can be white, blue, red, lavender, pink, and purple. The color of the flower can also vary by the pH level of the soil. The higher the pH the more red the flowers will be, while the lower the pH the more blue.
After the blooming season the flowers go from green to brown. Once the flowers turn brown they can be cut off. The shrub should be pruned in winter to encourage flower growth in the spring.
Source: 500 Essential Garden Plants, Annette Timmermann, Rebo Publishers, 2004