They are native to the New World. When Spaniard Hernando Cortez invaded Mexico in 1519, he found dahlias to be a long-established favorite in the gardens of the Aztecs. Wonderful for cut flowers, dahlia blossoms range from dinner plate-size to only an inch across, depending on the variety.
Flowers are showy from mid-summer until autumn.
Some of the low growing varieties can be used as a colorful, inexpensive, summer hedge. There are many colors to choose from - rich reds, deep purples, pinks, orange and yellows. May is a good time to plant dahlia tubers. The tubers are then dug in the fall and stored during the winter in all but the mildest coastal climates. Starts are rooted cuttings taken from a mature dahlia plant.