Chrysanthemums come in myriad colors and flower forms, just in time to spruce up a tired flower garden or create a festive fall display. The garden centers are overflowing with these must-have bursts of color. Some gardeners have tried and failed to overwinter these mature mums. Gardening mistakes are the cause.
Gardening mistake No. 1: Not amending the soil of the planting hole. Mums are grown in a media of peat, perlite, vermiculite, bark, etc., far different from the soil in your garden. This media is more aerated and has better drainage. Add 4 inches of organic matter (compost, leaf mold or well-rotted manure) to the area before planting.
Garden mistake No. 2: Not all mums are hardy. Plant breeders have chosen chrysanthemums for their flower color, flower form and perhaps height. With breeding comes differences in hardiness.
Garden mistake No. 3: Improper watering. When planting chrysanthemums, only tease out the roots if they are encircling. This root ball/garden soil differentiation will cause the root ball to dry out faster than the surrounding soil even if it is amended. Check the area directly around the roots to determine if watering is needed.
Garden mistake No. 4: Not mulching. Mulching is great insulation for the roots to make it through our Illinois winter. In the spring, gradually remove mulch.
Garden mistake No. 5: Plant as early as you can. Plant in September rather than waiting for the blooms to cease. The earlier you can plant, the better root growth you will get before the ground freezes. Chrysanthemums used in fall displays and then transplanted late in the fall may not have a chance to prepare for winter.
Garden mistake No. 6: Not putting in a protected location. We know that our homes and landscapes can create microclimates much warmer than our designated zone 5b. Do not plant garden chrysanthemums in open, windy areas.
Garden mistake No. 7: Planting near lights. Chrysanthemums bloom when the days shorten and the nights lengthen. An overhead street lamp may interrupt this process, causing flower buds to not form.
Garden mistake No. 8: Cutting back dead plants. Leave the top growth as a form of insulation in the winter and cut back when you see new growth in the spring.
Garden mistake No. 9: Not pinching. If you have successfully overwintered, pinch your chrysanthemums by July 4 for compact plant. Some gardeners pinch a few times throughout the garden season. This is how greenhouses and garden centers provide round mounds covered in flowers.