Plant dahlias tubers after the danger of spring frost has passed and soil has warmed to a consistent 60 degrees Fahrenheit. Dahlias require full sun, six to eight hours per day, consistent deep watering two to three times per week, and food every three to four weeks. Dahlias, many of which make fantastic cut flowers, bloom in mid-to-late summer and look their best when most other flowering plants are past their prime. They are hardy in USDA hardiness zones 8 through 11, and in colder climates, you must dig up and store dahlia tubers over the winter. Here are 14 dazzling dahlias to grow in your garden.