With flowers in the cheeriest hue, 'American Sun' Decorative Dahlia brings a joyful glow to garden beds and borders and lights up cut flower arrangements. Dahlias are perennial in zones 8-10, but in cooler zones, tubers can be dug after frost comes, stored over winter, then re-planted the following spring. Grow Dahlias in a sunny spot, in average soil that drains well. Keep moisture consistent once they begin to grow and enjoy a non-stop color parade.