The 'Ben Huston' dahlia is one of thousands of beautiful varieties of this flower. "Dahlias are on a huge upward rise in popularity," says Scott Kunst, owner of Old House Gardens in Ann Arbor, Michigan, a mail-order nursery specializing in heirloom bulbs. "Dahlias are as easy to grow as tomatoes and, like tomatoes, are worth the effort."
The 'Akita' dahlia, classified as a novelty fully double, resembles a chrysanthemum with white tips.
'Mingus Ida' is an example of the laciniated dahlia. Natives of Mexico and Central America, dahlias were named after a Swedish botanist, Andreas Dahl, after specimens arrived in Europe from Mexico around 1789. One of the longest-flowering tender perennials, they bloom six to eight weeks after they're planted.
The 'Kelvin Floodlight' is one of the larger dahlia blooms. Because there are so many variations, dahlias are placed into classifications based on 19 forms and 15 colors. Dahlia blooms can range in size from 1 to 17 inches across; the plant itself grows from 2 to 20 feet high.
Place dahlias in full sun. Plant tubers after the last frost-free date for your area, or start them in pots inside four to six weeks earlier. Dahlias like well-drained, rich, moist soil. Water and fertilize regularly.
Add a floral preservative to hot water (about 130 degrees). Wait to arrange fresh-cut dahlias until the water cools. Change water and recut the stems every day for a display that lasts three to six days.
'SB's Sunny' is a miniature ball dahlia. For information about this and other dahlias, search for downloadable dahlia pamphlets written by James Romer of Iowa State University Extension at extension.iastate.edu . For helpful articles, including Rick Peters' no-fuss method for storing dahlia tubers, and to order a copy of the book he helped write, visit the "guides" and "purchasing" links on the website of the American Dahlia Society at dahlia.org .
Dahlia Hill, owned and maintained by the Dahlia Hill Society of Midland, Michigan, displays some 3,000 dahlias (more than 200 varieties) from July to first frost. Dahlia Hill, 2809 Orchard Drive. (989) 631-0100; dahliahill.org 
Shown in picture: 'Pam Howden' dahlia.