What makes a chrysanthemum "hardy"? There are both hardy mums and florist mums. The hardy mums are grown to over-winter better in areas like ours. They send out "stolons", which are the side buds that make for a full, round plant with smaller flowers that are much more profuse than the florist mums. Popular cultivars are both the "cushion" mum (which is like the yellow mum pictured) and the daisy mum (with its colored center and smaller rows of petals.
Plant hardy mums outside as soon as you can, so they establish roots quickly. The soil should be well drained, and enriched with compost. Do provide water if the season is very dry. Mums prefer at least 4 hours of direct sunshine a day to bloom properly. The plants are considered "photoperiodic", meaning that they bloom in fall because of the shorter days and longer nights. In the spring, it's best to "pinch back" the buds about an inch at Memorial Day and 4th of July, in order to get the proper bloom time. After blooming, mums benefit from a layer of mulch, or at least do not cut back the old stems to provide some winter protection. Uncover in the springtime. And don't forget, mums will take a light frost but not a hard one. You may need to get the sheets and towels out and do some night-time covering!
Plant your mums now for new green growth and enjoy the flowers as they open. When the mums are done, add a pumpkin or gourds under the leaves of the plant for additional fall interest.