Climate

• Antique hydrangea plants were not very tolerant of the cold, but newer hydrangeas will happily survive in climates that get as cold as minus 10 degrees Fahrenheit over the winter. Growing zones 10 through 6 are all appropriate for the hydrangea.
  
  

Color Variations

• One interesting thing about hydrangeas is that you can change the color of the flowers from year to year by tinkering with the pH of the soil. The more aluminum a hydrangea plant can access from the dirt, the bluer the flowers will be. In order for the plant to access the aluminum, you want to have a low pH. The higher the pH, the pinker your flowers will tend to be.
  
  

Pruning

• Hydrangeas are perennial shrubs and require a bit of maintenance and upkeep from year to year. Unlike many other plants, it is actually recommended that you prune the hydrangea in the winter, since the lack of leaves will make it easiest to get to the stems. Remove approximately one-third of the old stems each year to keep optimum blooms each spring.