The Homeowners Column

The Homeowners Column

Chrysanthemums for Fall Color

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

By now the petunias are looking straggly, worn out and in need of a good pruning. It's time for some garden excitement. Chrysanthemums have long been regarded as the flower for late season color. And, oh, what color they have in shades of yellow, pink, orange, red, bronze, purple and white. The flower types are equally as diverse from daisy, anemone, semi-double, buttons, pompoms and double.

Mums are short day/long night plants. Flowers are initiated when the daylength (actually the length of darkness) reaches a certain period. They naturally bloom as the days get shorter in the late summer. The period of darkness required to initiate blooming depends on the cultivar. By careful cultivar selection a garden could have blooming mums from August through October. Florist mums require a very long night so they do not set buds until late in the season and are often killed by frost before they ever have a chance to flower in the garden.

Most outdoor mum varieties are now listed as garden mums and not hardy mums. Cold tolerance is only one essential attribute for mums to live through the winter. Mums are best planted in full sun in well-drained soil. One of the reasons mums fail to live through the winter is overly wet soils in fall and winter. Soil drainage can be improved by adding compost to the soil and planting in a slightly raised area.

Mums are best planted in spring to assure better establishment and therefore winter survival. In spring mums are generally available as four inch pot plants, but they will grow quickly into sizable plants by fall. In order to produce bushy well-branched plants, mums need to be pinched two or three times during the growing season. Pinching requires the removal of about an inch of the tip of each branch or shoot by snapping it out with thumb and forefinger. The first pinch is done when the plants are about six to eight inches tall. After these branches grow six inches or so they should be pinched again continuing until July 4th. Pinching promotes numerous flowers and reduces the need for staking.

For fall-planted mums flowering takes precedence over root growth and establishment. The second best time for mum planting is late August to early September to allow at least some time for establishment before cold weather sets in. Don't wait until December to plant your mums.

Mums have a shallow, fibrous root system so water thoroughly during hot, dry weather. After flowering has ceased, trim off old flowers and fertilize with a low nitrogen fertilizer such as 5-10-10. Mums also respond well to additional fertilizer during the growing season.

After the ground freezes trim off the dead stems and place them back on top of the plant crown. Mulch with shredded leaves for additional winter protection. If you buy mums this fall, look for plants in bud with only a little color showing. Plant as soon as possible and keep soil moist but not soggy. The color dresses up a garden so much I don't care if they become fall annuals.

The Idea Garden on south Lincoln Avenue just gets better every year. Please join us at the garden for the fall Saturday workshops at 10:00 am. No fee or registration is required.

September 9 Fall Vegetable Crops
Discover what and when in planting, harvesting and storing vegetables from the Idea Garden experts, Master Gardeners Jean Dawson and Gloria Levitt.

September 16 Dividing Perennials
Fall is a great time to divide your perennial plants that have grown too big for their space. Learn the how-to's and what-not's from Master Gardener Bette Hughes.

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