Hydrangea :

With its big, bushy head and intense colors, it’s no wonder the hydrangea represented”vanity” in the language of flowers.
The color of one of the most popular varieties changes from bubble-gum pink to sky blue, depending on the acid level of the soil. Other popular shades include burgundy and white. A stem or two of this moderately priced, scentless shrub flower helps fill out arrangements and bouquets.