If you like to make dried wildflower wreaths and dried flower gift tags, hydrangeas are easy to dry.
Cut off flower heads past their prime and hang from string tied to a rod in a cool dark place. We have them hanging from a rod hanging over the sink in the garage.
You can use hydrangeas as they are, which is what I do. They make a great filler in wreaths. If you need a little more color, use a spray. The dried flowers will hold the color nicely!