Purple Hydrangeas
Only hydrangea macrophylla (bigleaf or mophead hydrangeas) flowers can turn purple. This is caused by the pH of the soil In slightly acidic or neutral conditions (pH 6 to 7). Some hydrangeas will keep purple even in different soil conditions, but that happens less frequently.
More Information Here:
How To Turn Hydrangeas Purple
Purple Hydrangea Meaning
Purple hydrangeas symbolize a desire to understand someone deeply. It can also be a symbol for someone with an abundance of wealth.
Other Hydrangea Colors: