Identification

Zinnias are annual garden flowers that can be grown from seed or purchased in flats at the beginning of each growing season. Dahlias are grown from tubers and so are (technically) perennial flowers, but in cold climates the tubers must be lifted in the winter and replanted in spring.

Features

Both zinnias and dahlias like lots of sun, are native to Southwestern climates with year-round warmth, and enjoy slightly acidic, well-drained soil. Zinnia and dahlia flowers can be small as buttons or as large as dinner plates. Colors range from pink to yellow to orange to red to various brilliant combinations of these.

Types

Zinnias and dahlias are members of the botanical order Asterales and family Asteraceae. Dahlias come in more than 30 species with more than 20,000 cultivars. Horticultural societies have sprung up around their appreciation and cultivation.

Benefits

Zinnias and dahlias both are easy to grow and make excellent cut flowers. Both attract butterflies, bees and hummingbirds. Many dahlia varieties do produce seeds, but the flowers will not grow true from them: you have to plant the tubers to get the dahlia flowers.

Considerations

Beginning gardeners may find zinnias a bit easier to grow than dahlias. Zinnia seeds are less expensive than dahlia tubers and do not have to be lifted each fall. Zinnias are so easy to grow from seed that finding flats of zinnia flowers may be difficult in some parts of the United States. The wide variety of dahlia cultivars often attracts more experienced gardeners.

Source:

Department of Horticulture, University of Wisconsin, Madison: Zinnias

Times Beacon Record: Zinnias and Dahlias: Two Beautiful Summer Flowers

More Information:

The Long Island Dahlia Society: Home Page

The American Dahlia Society: Home Page