Extensive breeding complicates the identity of modern garden zinnias. Although they are products of several species, most identify simply as Zinnia elegans. They exhibit a broad range of floral color and form. Short varieties grow only a few inches tall. Large varieties grow as tall as two and a half feet. They are warm season annuals that bloom until frost.

The two to four inch wide flowers bloom in phases as long as the weather is warm. Their floral color can be yellow, orange, red, purple, pink, salmon, chartreuse or bronze. Some varieties have striped or freckled flowers. Some resemble daisies, with big petals around prominent centers. Pom-pom types produce puffier flowers with nearly obscured centers.

Zinnias enjoy good exposure and rich soil. The paired and very slightly raspy leaves can be susceptible to powdery mildew. Removal of deteriorating flowers promotes continual bloom. However, a few can remain to produce seed for the following season. Their seed should be sown as soon as possible after the last frost. Zinnias are excellent cut flowers, and can last for a week or even two.