Many flower lovers wrongly presume that potted or garden mums are only grown as annual flowers. Although they have very specific growing requirements, anyone with a fondness for Chrysanthemums can plant these delightful flowering plants in their yard or garden and have them return to bring joy to the fall landscape year after year.
Where and How to Plant Mums
Choose a location that will give your plants at least a half day of full sun, and keep them in complete darkness for at least 12 hours. You also need to protect them from cold, dry north or northwesterly winds. Make sure the planting area won’t be too shady because plants that don’t get sufficient sun are more likely to suffer from foliar diseases.
Also make sure that your plants are at least 20 feet away from any street or other light sources. Hardy or garden mums are photoperiodic flowers, meaning their ability to flower is largely dependent on shorter days, cooler nights, and at least 12 hours of darkness. The darkness is necessary for best bud formation.
Preparing Mums for Planting
If you are going to plant your mums in spring (which is the best time to do it,) keep the plants indoors until the flowers fade and you don’t have to worry about frost. Cut the stems to about ½ to 1/3 their mature height when flowering. You want to plant them in fertile, well-drained soil in a sunny location. Amend your soil by adding compost, composted manure or peat moss. Once you see 3 to 4 inches of new stem growth, pinch off an inch of growth, using your thumb and forefinger above the node where leaves sprout. Continue pinching plants throughout the season to keep plants full and compact.
If you transplant mature plants in spring, add granular all-purpose fertilizer to your planting soil. Immediately after planting, water your new transplants deeply using a balanced liquid fertilizer with a 20-20-20 concentration. From then on, until the end mid to late July, only fertilize plants once a month, using either a liquid or granular fertilizer. If you are transplanting your plants in fall, don’t use any fertilizer. Deep watering after planting is essential.
Space larger plants at least 1 ½ to 2 feet apart. If you have smaller starter plants, cluster plants closely together to create the effect of a mass planting. Throughout the growing season, water mums regularly, but don’t allow the soil to get soggy. You just want to maintain even and consistent moisture in the soil. Pinch off flowers after they bloom for continual blooming throughout the growing season.
Immediately after your first freeze, protect the crown of your plants (the area where the roots and stems come together,) with a thick but loose layer of mulch. Pile about 2 inches of straw around the plants, but don’t cut the stems off because they protect the crown area. You will want to cut stems back in early spring.