There are approximately 40 recognized species of dahlia, which are native from Mexico to Colombia, and thousands of cultivated varieties. 'Dazzling Sun' comes from the Netherlands and produces large, decorative flowers that have yellow rays and a fiery red core. The flowers can measure 6 inches across and grow on plants more than 3 feet tall. Plant tubers or potted plants outdoors after the danger of late spring frosts has passed. Dahlias are not hardy in the Chicago area. After the first hard frost in the fall, lift the tubers, shake them free of soil, and store them in a cool, dry location, nestled in pine shavings until the following spring.