By Cindy Haynes
Iowa State University
Chrysanthemums, or mums, are a dependable and colorful staple for the fall garden. They liven up containers on decks, patios or front door stoops and brighten beds and borders, just as other perennials and annuals are winding down for the season. Thousands of cultivars of mums are available for planting in the landscape or decorating your doorstep.
Variety of Flower Forms, Colors, and Plant Habits
Chrysanthemums are classified according to the shape or arrangement of petals. A dazzling array of flower colors and forms are available. Single mums have a single row of petals and bright yellow centers (like a daisy) -- while decorative, pompon, and cushion forms appear as all petals and no daisy-like centers. The petals may be rolled or tubular or even hooked at the tip as found in the spoon, quill, or spider flower forms. Varieties also differ for petal size. For example, anemone types have long and flat outer petals while the inner petals are shorter -- creating a crested effect.
Each form or shape is available in at least a dozen different colors -- the choices are overwhelming! Since mums are primarily fall bloomers, it is not surprising that seasonal colors such as orange, gold, maroon and burgundy are popular; but plants are also available in white, pink, lavender, yellow and other more pastel hues.
Twenty years ago mums were generally a one- to two-foot tall plant, both in the garden or in a container. Today there are tall cultivars, reaching over three feet tall, and dwarf cultivars, staying below a foot. Plants may be upright and shrub-like or creep more like a groundcover. Read the label carefully to make sure the mature size and shape of the plant will fit your space.
Cold Hardiness Issues
Growing mums successfully depends on matching the intended use with the proper cultivar. Chrysanthemums have a reputation as not lasting in the landscape, especially over the winter in many parts of Iowa and the Midwest. However, if you want a colorful display for a few containers in the fall, simply plant them, water them occasionally, and pitch them in the compost pile when winter arrives. If you want or expect your mums to persist and bloom year after year like a typical perennial, then proper plant selection, placement, and care will increase chances of survival.
Hardy and non-hardy cultivars of mums are available to the public. Don't assume that the mums you buy in the pretty baskets and bows from a florist or supermarket are hardy -- these are usually not hardy in Iowa. Instead, look for "garden" or "hardy" mums. These plants are often put on display outdoors at garden centers, discount stores and some florists. Look for cultivars bred in Minnesota. Cultivar names that start with "Minn" or even the shrub-like "Maxi-Mum" types are from Minnesota and have the genetics to survive an Iowa winter.
But being genetically capable of surviving the winter doesn't ensure survival. If you want to keep these plants for many years to come -- plant them in a sunny, well-drained location. Don't put them in containers on your door step, then plant them in the ground in November, and expect them to over winter. They require a period of establishment in the ground in the months of September and October to establish good root systems in preparation for winter. Sunny sites with well-drained soils are essential. Plants perform poorly (and often die quickly) in shady locations with wet soils.
For the first year or two, mulch heavily and don't cut the plants back in the fall. Wait until early spring to remove or clean up the old stems. The four inches of added insulation will help ensure survival over the winter. After a couple of years, plants should be well-established enough to survive without the added protection.
Finally, keeping mums healthy will mean a little extra effort in spring and summer. Mum plantings generally benefit from pinching, or cutting them back slightly, in early summer. This promotes branching, compact habits and more blooms in the fall. Chrysanthemum plantings also benefit from regular fertilizer and moisture applications early in the growing season. By late summer, fertilizer applications should stop -- signaling to the plant it is time to bloom and prepare for winter.
Whether planted in a solid mass of a single color or many colors mixed together to form a living tapestry in the garden, fall just wouldn't be the same without chrysanthemums. No other flower can provide such a dramatic climax for your landscape before the arrival of winter.