WW-03160     1987  

Minnesota Report 209-1986

ROSY GLOW MUM

Rosy Glow, the first garden chrysanthemum to be released as the Minnesota Agricultural Experiment Station enters its second century, should be a winner. It is the sixty-sixth garden chrysanthemum bred at the University of Minnesota for the Upper Midwest.

Rosy Glow (78-28-3) displays a full canopy of 4-inch, deep rosy-pink, incurved, double flowers with yellow centers atop stocky, spreading plants. The stiff stems are clothed with clean, medium-green foliage on plants 15 inches high and 18 inches wide. Flowering usually begins in early September in the St. Paul area. Rosy Glow is propagated easily, but not quite so easily as Centerpiece which is exceptional in that respect. Parents are Minnesota selections 75-28-14 and 75-63-5. Rosy Glow is adaptable to pot culture for spring-flowering plants, but it grows a bit tall unless given short days or chemical growth regulator treatment.

Disease detection tests of original stock plants of Rosy Glow were conducted by F. L. Pfleger and R. J. Zeyen of the Department of Plant Pathology.

Chrysanthemum Culture

Planting Time-Plant chrysanthemums in spring after all danger of killing frost has passed. Use small plants derived from rooted suckers of old plants or new plants from a local source. Larger plants in various stages of development may be planted anytime during the summer or early fall.

Soil, Site, and Fertilizer-Garden chrysanthemums grow best in well-drained soil in full sun. Plants grown in semishady locations tend to grow taller, have weaker stems, and bloom later in the fall. Incorporate peat moss, compost, or well-rotted barnyard manure and superphosphate (3 to 5 pounds per 100 square feet) into the soil. If you use peat moss or do not add organic matter, apply a commercial fertilizer, such as a 5-10-5 or 10-10-10 formulation, in the spring according to package directions. Sidedressing plants with a complete fertilizer in early August, especially in years of abundant rainfall or irrigation, is recommended also. If the fertilizer applied in the spring is a slowly available type (one that is released as the plant needs it), such as coated or organic fertilizer, the second application may not be necessary.

Cultivar Selection-Select cultivars that will bloom before the end of September in the Twin Cities area. Later- blooming cultivars will fail to bloom before damaging or killing frosts in most years. Note that cultivars usually bloom earlier in northern Minnesota and later in southern Minnesota, in accordance with environmental differences and planting date. A descriptive table of the more popular University of Minnesota introductions is included in a fact sheet, Garden Chrysanthemums (FS-1121), available from county extension offices in Minnesota.

Pruning-When plants are about 6 inches tall, pinch out the tips to induce branching and to produce stockier plants. Pinch lateral branches when they have grown 6 inches. Pinching after July 4 delays flowering.

Watering-Do not let plants suffer from a lack of water. One good watering or rain per week, the equivalent of 1 inch of water, usually is adequate except in extremely hot weather or with light or sandy soil.

Insect and Disease Control-Spraying or dusting with an all-purpose insecticide-fungicide mixture twice a month from June through September is recommended.

Late Flowering-Possible causes include:

• Wrong cultivar selection
• Insufficient sun (shaded)
• Insufficient fertilizer Insufficient water
• Pinching too late
• Root competition from nearby trees and shrubs (which is injurious to most plants)
• Unusually hot weather, especially nights, in August (cultivars vary in their response to such weather)
• Unusually cold weather in late August and September
• Insect injury
• Disease injury

Overwintering-To be reasonably certain of carrying plants over the winter, use one of these methods:

• Dig plants in the fall and plant them in pots, flats, or similar containers. Keep them in a cold cellar over the winter at a temperature of 33 to 38 degrees F. Plants overwintered in this manner need no care except occasional watering.
• Dig plants in the fall and plant them in a cold frame in a protected location. After freezing weather (November), mulch heavily with leaves, hay, or straw. Then cover the cold frame with sash, boards, or plastic film, and cover all with 6 or more inches of mulch.
• In late fall, remove rooted suckers from around the base of the plant. Put them in small pots and carry them through the winter as houseplants. Pinch off tips when shoots are 6 inches long. Instead of pinching, you may wish to take 3-inch-long cuttings when the shoots are 6 or more inches long.
• Although no cultivars are consistently hardy under Minnesota winter conditions, sections of clumps frequently survive the winter. Divide such overwintered plants if there are four or more growing points.

Dividing-If the entire clump survives the winter, it is preferable to divide it into small clumps with two or three growing points.

Spring pot plants-Attractive blooming plants grown in small pots are available in the spring. After flowers fade, cut the plants back to 3 or 4 inches from the ground and plant them in the garden for fall flowering. Young, nonflowering plants are also available and are quite satisfactory.

Produced by Communication and Educational Technology Services, University of Minnesota Extension.

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