The main difference between garden mums and florist mums is that garden mums are hardy and can survive frost and winter months, while florist mums are less hardy and only survive in warmer climates. This is because garden mums have an advanced root system, while florist mums do not.
Garden mums produce advanced underground shoots and stolons, which enable them to survive throughout the year, including during winter months. Florist mums produce few or no stolons and can only be grown for a short growing cycle. Florist mums are often planted indoors or as short-term bedding plants during the summer months because they are easily killed during the winter months.
The United States Department of Agriculture gives garden mums a higher hardiness rating, and they can be planted in planting zones 5a through 9b. Florist mums are planted in zones 8 through 10, which are in warmer climates.
All mums generally bloom when daylight hours get shorter. Florist mums require about 11 weeks of shortened daylight time to bloom, while garden mums require only six weeks of shortened daylight time to bloom. To increase their chances of survival, florist mums need at least six hours of sunlight and plenty of moisture.