Gerberas have a long vase life
Part of the reason gerberas are so commonly used in bought flower bouquets is that they have very long vase lives. To help your gerbera bouquet last longer read How to Care for Fresh Flowers - Gerberas. They are also popular due to their wide range of colors - they can be light to dark yellow, orange, pink, scarlet, deep red and more. Aside from looking great in bouquets or vases, the flowers are also used a lot in landscaping and outdoor gardens as accent buds.
Gerberas are in the genus family of sunflowers, daisies and asters. Many people refer to gerberas as daisies, though they are technically just in the same family, rather than the same flower.