The chrysanthemum is a popular perennial flower that provides garden color into late fall. Chrysanthemums can bloom beautifully from late August until the first hard frost.
Be careful, though, when you buy them. Most florists' mums are not designed to be planted outdoors in this climate. Ask for Minnesota-hardy mums, developed by the University of Minnesota. They are ideal for flower borders and are more likely to survive our winters. Buy your garden chrysanthemums as young plants in mid to late spring. The plants are usually 3 to 5 inches tall when you buy them. They have several side shoots. Depending on variety, they'll grow from 10 inches to 2-1/2 feet tall - or more.
Before you plant, work the top 8 to 10 inches of the soil. Many gardeners also incorporate peat moss or compost into the soil. This helps hold water and nutrients and improves the soil's structure.
There are many varieties of mums with different growth characteristics. It's important to know the type you're planting so you can give them the right space. Plant tall varieties at least 12 inches apart. Give spreading varieties a little more room to prevent competition between plants.
Pinch off 1/2 inch from the branch tips to stimulate side branching. Pinching is done repeatedly in spring and early summer. Don't pinch after July 4th or your mums will not bloom early enough.
Keep the soil relatively moist. During dry weather, wet the soil 6 to 8 inches deep. Mums can be heavy feeders. Fertilize them in spring and again, mid-summer.
For more information contact your University of Minnesota Extension Service county office.
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