Blue Hydrangeas
Hydrangeas that are able to bloom blue in color are also able to produce pink and purple hues. The pH of the soil determines this. In order to have your hydrangeas produce blue blooms, you will need to increase the pH of the soil. There are several ways to do this, but the easiest way to do this is add coffee grounds to the soil. Cut up citrus peel will also add acidity to the soil.
More Information Here:
How To Turn Hydrangeas Blue
Blue Hydrangea Meaning
Blue hydrangeas symbolize frigidity. It can be turning down a romantic proposal, asking for forgiveness or expressing regret.
Other Colors: