If the winter snow has thawed just once, chances are your mums are lacking sunlight or exposed to high winds. However, if it is early in the season, put hardy mums purchased at a garden center on the list with pipes, and with pruning and simple sheltering techniques, you can prevent your roots from freezing and full-bodied blooms on existing stems will return for another marvelous season.
Chrysanthemums, or Dendranthema, are perennials native to Europe and parts of Asia and by definition live for over two years. Stephanie Cohen and Jennifer Benner, authors of The Nonstop Garden, call these late-season flowers “among the kings of the autumn bloomers,” and specify that they perform well in temperatures fluctuating between -40 and 30 degrees Fahrenheit. The American Horticultural Society (AHS) provides that the latest types bloom from fall to early winter but, “may disappoint in a cold, wet fall.” In other words, mums demand drainage!
Spring-planted mums have the best chances of overwintering, especially, when slightly acidic soil is fortified with compost to encourage root growth. Removing dead flowers must be tackled after flowers have “died” naturally following frost, and turn brown. The AHS recommends cutting stems to four inches (10 cm) above ground. The final step is putting down dry mulch such as straw or evergreen needles, to keep the ground insulated and shoots from springing into action too soon. Mulch should be removed as the ground softens. Placing plants in a cold frame—structures that use solar energy, to create a microclimate within a garden—is another option, though moisture and exposure should be monitored using this method as well.
Still feeling up unsure about caring for your chrysanthemums? Visit the National Chrysanthemum Society and order a free beginner’s handbook by mail. A digital edition of The American Gardener is also available for members on their website.