Pruning Mums During the Winter

Chrysanthemum Facts

• Chrysanthemums are native to Asia -- the chrysanthemum is the national flower of Japan. Seeds sown in the spring will bloom in the fall and, when new growth is pinched back until mid-summer, the plant branches freely to create a 2- to 3-foot mound of blooms by fall. Although pinching must stop in early July to allow the plants to form buds and bloom by fall, deadheading spent blooms will prolong flowering through early frosts until the first hard freeze.

New Life

• While the chrysanthemum blooms profusely in the fall, new plants form at growth nodes on roots that run near the surface of the ground. When cold weather begins, the parent plant shelters the baby plants and, if early snows cover the plant, the baby plants will continue growing. Unfortunately, the parent plant also continues to draw nutrients away from the baby mums until it dies back completely -- and provides a handy winter shelter for rodents, insects and fungi. In order to allow the new plants to thrive, the parent must be sacrificed.

Procedure

• Once the parent plant dies down in early winter, cut it back to the ground and remove the parent plant top growth. The main stem may still be green. Cutting the plant back to the ground will encourage new growth near the main stem -- the parent plant may rise again. Once the old plant is cleared away, nothing else needs be done in warmer climates as the babies may continue growing and the pinching-back process can recommence until the new plants are separated and moved to their new positions in the garden. In colder climates, where temperatures stay below freezing for weeks or more, mulch the plants with about 4 inches of well-rotted compost or mixed organic mulch.

Florist Chrysanthemums

• Florist’s chrysanthemums, raised and manicured in greenhouse conditions, seldom survive over the winter in cooler climates, but have a fighting chance in warmer areas where freezing periods are short. These special chrysanthemums are typically a pot full of plants, crowded together and given extra fertilizer. Prune the plants as soon as the flowers fade, no matter what the season and plant them in the garden to see if they’ll sprout again -- or keep the plant in a cool garage or basement until the temperature warms above freezing in the spring to protect the tender plant. If the plant grows again, pinch, deadhead and cut the plant in the winter as with a hardy garden plant.