BLESSINGS IN BLOOM: Chrysanthemums

By Kerry Peetz

The fall equinox and the first day of autumn arrives on Sunday, Sept. 22, 2024, at 08:44 a.m. EDT in the Northern Hemisphere. The equinox occurs at the same moment worldwide. So, it’s official — fall is here!

While some plants in the garden are looking scrappy this time of year there are bursts of color provided by chrysanthemums. Called “mums” for short they are a popular perennial and can be found around our diocese marking the change from summer to fall.

Mums were brought into cultivation before 1000 B.C. and adopted as the national flower of Japan in 910. What’s in a name? In the case of the chrysanthemum, quite a lot. This plant has always been referred to as “yellow flower” — chrysanthème in French; chrysantemo in Portuguese, Spanish and Italian; krysantemum in Scandinavian languages; and in English, German and Dutch — chrysanthemum.

Chrysanthemums arrived in Europe in the 1600s and caught the attention of the Swedish botanist, Carl Linnaeus, who earned fame and respect for developing a scientific system for naming plants. Linnaeus noted the Asian plant was similar to a corn marigold found in southern Europe. He chose the name chrysanthemum. Later, an unknown botanist changed the name to chrysanthemum indicum. Then, in 1961, Russian botanist Nickolae Tzvelev took another look at chrysanthemums and the corn marigold and decided they were not as similar as once thought. Then, you guessed it, he changed its name to Dendranthema x grandiflorum. Internationally this caused a lot of fuss and confusion. Finally, in 1995, a formal proposal was made to the International Botanical Congress (the ruling body that determines specific plant names) requesting the name to be returned to chrysanthemum. The International Botanical Congress did indeed rule that the garden mum should return to its original name. Thanks be to God!

Mums have a wonderful range of colors from creamy white to dark burgundy. They have numerous growth habits from small dwarf plants to larger shrub-like plants. They are considered easy to grow and if the appropriate variety is planted in the correct place the blooms can be admired for decades. 

When planting from rooted cuttings, divisions or rooted suckers (from older plants) springtime is the best time after all danger of frost has passed to put them in the ground. The larger container plants purchased from local garden centers may be planted anytime during the spring, summer or early fall.

Garden chrysanthemums grow in a variety of our Colorado soils but must have excellent drainage conditions. Growth is poor and winterkill likely in poorly drained wet soils. Sunny locations are best. Plants in partial-shade locations will be taller, have weaker stems, and bloom later in the season.

Most mums maintain a bushy, compact shape if pinched or pruned regularly. Although newer cultivars do not require pinching, the traditional method has been to pinch off the tip to promote branching and produce stockier plants. Repeat pinching on side branches when they have grown 6”. Pinch two or three times before the Fourth of July to assist in flowering before frost. Water plants regularly if the summer has been dry or if soil is light and sandy. Apply 2-3” of mulch such as grass clippings, compost, or shredded leaves to conserve soil moisture and reduce weeds.

Mums can be prone to disease. Prevention of many of these diseases can be accomplished if they are planted in a sunny location, make sure purchased plants are free of disease and insects, avoid overcrowding and allowing for plenty of good air circulation. Typical problems include verticillium wilt, septoria leaf spot, powdery mildew, aphids, leafhoppers, leaf miners, and spider mites. Before using a pesticide, diagnose problems carefully and correctly. When in doubt contact our local Master Gardener Help Desk located at the El Paso County Extension Office for further information.

“By all these lovely tokens, September days are here. With summer’s best of weather and autumn’s best of cheer.” — Helen Hunt Jackson.