Majestic Mums
H-1094, June 1995
Ronald C. Smith, Extension Horticulturist
Dale E. Herman, Horticulturist, Department of Plant Sciences
The majestic mums of today have undergone many changes. First, their nomenclature is now botanically known as Dendranthema grandiflora. Next, their hardiness and blooming times have been greatly improved for North Dakota gardeners. They come through the winter with greater success and their flowering can often be enjoyed as much as two weeks sooner than in the past. To achieve this dependable blooming and winter hardiness, mums must be grown in a way that assures full sunlight, ample water, well-drained soil and proper fertilization.
Mums offer a great diversity in plant habit, flower color, and form. This makes them excellent candidates for both landscaping and cut flower purposes. Many of the cultivars introduced over the past 10 to 25 years were selected for mounded form, called cushion mums. These are more compact and densely self-branching, and provide a great showing of flowers. In the autumn garden, these bright, fresh splashes of color are unrivaled. They may be used to advantage in landscape and foundation plantings, or in the garden. On public grounds, such as parks, mass plantings are very effective and showy.
Cultural Practices
Well rooted cuttings or vigorous divisions of overwintered clumps qualify as acceptable planting stock. Spring blooming mums from garden centers or florist shops that are typically popular around Mother's Day make poor selections for permanent garden plantings that will be productive in the fall.
Mums are best planted after Mother's Day in the southern half of North Dakota, and after Memorial Day in the rest of the state. Be sure the plants purchased have been hardened off and that you are prepared to offer protection should a hard frost be predicted. Overwintered plants that are showing vigor may be divided and moved in mid-May, while the weaker ones can be moved once vigorous growth is apparent, generally after the Memorial Day weekend.
Mums do well in most well-drained and fertile garden soils. If in doubt, add peat moss or compost. Work a little 5-10-5 fertilizer into the soil around each plant in May, followed by a good watering.
Spacing of mums is variable: 18-24 inches is the norm, under intense management, 12 inches is acceptable. Where supplemental water will be lacking, a wider spacing is suggested. An important factor in good growth is to locate them where they can receive most of the day's direct sunlight.
Mums are quite drought tolerant plants, often going through a growing season without supplemental watering. When it does become necessary to water during extended periods of rainless high temperatures (7 to 10 days), provide water through a soaker hose or a breaker that allows a slow trickle of water from the opening. Be sure the soil is saturated completely to a depth of 4 to 6 inches. Try to avoid watering via overhead sprinkler or hose. Getting water on foliage encourages disease problems.
The practice of pinching mums will produce sturdy, well-branched plants. The first pinch should be done when the plants are about 6 inches tall (generally late May or early June). Simply remove the soft tissue growth with the thumb nail and forefinger. The side branches or shoots that result are themselves pinched when they get about 6 inches in length. All pinching should be done before the Fourth of July, as some cultivars are forming flower buds around this time, and pinching later would only result in non-flowering plants.
The blooming period varies with the weather conditions of the season. Cool, rainy summers will result in a different time of bloom than one which is hot and dry. Landscape lighting near mum plantings could be the cause for a delay in blooming, since mums are known as "short day" plants. Moving them, or covering those particular mums at sunset will help to bring them into a more timely blooming period.
Once the mum flowers have been blackened by late autumn frosts, the gardener can do one of two things: After the soil is hardened by a layer of frost, apply a light mulch (2 inches of straw) around the plant, leaving the top to help trap snow; or, the plants can be dug and stored in a cold frame over the winter. In spring (late April-early May) dig the plants that have remained in the ground and divide them into vigorous growing shoots for replanting.
Cultivar Selection
Cultivars of mums are numerous, with each year adding many new selections. NDSU has trialed many cultivars, and has introduced one, known as Dakota Sunburst, Dendranthema grandiflora `Hildete'. It flowers early, with a generous profusion of deep, gold-colored blooms. The cultivars on the following page have been found to have merit from our trial observations.
------------------------------------------------------ Blooming Color Season Height: Flower Size ------------------------------------------------------ White Daisy White Mid Season Medium; medium; single Drifted Snow Early Medium; medium Minnwhite Mid-late Low; small Morden Everest Mid season Low; medium Poise Early Tall; medium Powder River Late Low; medium Snowsota Early Medium; medium Wee Willie Early Low; small White Darlingmum Late Low; small ------------------------------------------------------ Cream Mellow Moon Mid-season Medium; large Morden Cameo Early Medium; medium ------------------------------------------------------ Yellow Goldstrike Early Medium; medium Little One Mid-season Low; small Minnglow Mid-season Low; medium Minnyellow Mid-season Low; medium Morden Canary Early Low; medium Morden Eldorado Early Low; medium Muted Sunshine Early Medium; medium Prairie Sun Early Tall; medium-large Sea Urchin Mid-season Medium; medium Wayzeta Late Tall; medium Wendy Ann Early Tall; large Yellow Darlingmum Mid-late Low; small Yellow Glow Mid-season Medium; medium ------------------------------------------------------ Gold Buff Best Regards Mid-season Tall; medium-large Companion Early Tall; medium-large Golden Jubilee Mid-season Tall; medium-large Golden Regards Mid-season Tall; medium-large ------------------------------------------------------ Orange Compaigner Early Medium; medium Superior Early Medium; medium Sunny Glow Early Medium; small ------------------------------------------------------ Red Daisy Red Mid-season Medium; medium; single Flamboyant Late Tall; large Redheart Late Tall; large Red Headliner Late Medium; large ------------------------------------------------------ Maroon Maroon Pride Early Medium; large Minngopher Mid-season Medium; medium ------------------------------------------------------ Bronze Brown Eyes Mid-season Low; small Minnautumn Mid-season Medium; medium Morden Delight Early Medium; medium Zonta Early Medium; small ------------------------------------------------------ Purple Hoback Mid-late Medium; medium Morden Fiesta Mid-season Low; medium ------------------------------------------------------ Lavender Centerpiece Mid-season Medium; large Grandchild Mid-late Medium; large Lindy Mid-season Tall; large Lovely Lass Mid-season Medium; large ------------------------------------------------------ Pink Bonnie Blush Mid-season Low; medium Cameo Mid-season Medium; small Pink Darlingmum Late Low; small Minnpink Mid-season Low; small Sachet Mid-season Tall; large ------------------------------------------------------ Rose Minnqueen Mid-season Medium; medium Rosy Glow Mid-season Low; large ------------------------------------------------------
H-1094, June 1995
