In their native habitat, stretching from the southern U.S. to Chile, plants of the Zinnia genus are perennials. They are particularly abundant in Mexico. Gardeners in colder areas commonly plant the zinnia as an annual. It has long been a favorite garden plant, desired for its bright flowers colors, which come in every shade except blue. Both single- and double-flowered forms exist, the latter including beehive, dahlia and cactus shapes.
In its native Mexico, the Spanish referred to the zinnia as "mal de ojos" (which literally translates as sickness of the eyes), thinking it a small and unattractive flower. The seeds were sent to Europe in the 18th century. It received its name from a German medical professor named Johann Gottfried Zinn, who provided the first written description of the flower. (It is an interesting bit of trivia to know that his name is not only attached to a flower, but because of his work on the study of the eye, a part of the eye is called the zonule of Zinn, or Zinn's membrane.)
It was not until the late-19th century that the zinnia became more widely used as breeders in Germany, Holland and Italy began selecting zinnias for their desirable characteristics. Types called Pumila Mixed, Mammoth and Striata made their way to the United States, where they were widely planted.
Around 1920, a variety called Giant Dahlia was named by John Bodger of California's Bodger Seeds Ltd., who discovered it as a natural mutation. Within the next few years he selected from this strain a large flat-flowered type called California Giant. Available in separate colors and considered an innovation in plant type and form, it was awarded a gold medal from the Royal Horticultural Society of England.
The 1950s brought more new zinnias, including the tetraploid State Fair (a tetraploid is specially bred with extra chromosomes for larger flowers and greater vigor), and a dwarf selections called Persian Carpet and Old Mexico. More new strains came from breeder John Mondry, whose discoveries led to the dwarf hybrid Peter Pan series.
Zinnia breeders continue to engineer new flowers for today's gardens. Recently Zinnia angustifolia and Zinnia elegans were crossed to create the Profusion series, which combines the best of both types for a compact, colorful zinnia that is resistant to heat, humidity and disease and requires no dead-heading. There seems to be no end to gardeners' love affair with this charming flower, and it was named the Plant of the Year 2000 by the National Garden Bureau.