Above picture: chrysanthemums of varying colors. Photo by John E. Woodmansee
The Autumnal Equinox will be on Sept. 22, 2022, signaling the first day of Autumn. If you go to nearly any garden center in autumn, one flower that’s almost sure to be available is the chrysanthemum. It is also known as the garden mum, and has earned the generally accepted appellation, the “Queen of Autumn.” Used as vibrant fall accents, this garden beauty delivers on color – offering shades of yellow, orange, red, purple, bronze, pink, and white.
Dr. Michael Dana and Dr. Rosie Lerner authored a Purdue Extension publication on chrysanthemums. The following information contains excerpts from their writing in the online publication.
Chrysanthemums are classified according to the shape and arrangement of petals. These types include single, pompon, cushion, anemone, decorative, spoon, spider, and quill.
Single, pompon, cushion, and anemone types normally are small flowered garden mums; usually, they are cultivars selected to bloom before killing frost.
Other varieties with 3” or larger blooms are often referred to as florist’s mums; these are grown under greenhouse conditions and they may be single, anemone, decorative, spoon, spider, or quill types. According to Dana and Lerner, florist’s mums may be planted outdoors (in spring) for rebloom in autumn, but are not likely to survive Indiana winters.
Garden chrysanthemums are generally referred to as hardy, although high mortality may be experienced following extreme winters. Plants to be carried over winter should have winter protection in the form of mulch. The best time to apply mulch is November or early December after 2-3 episodes of temperatures below 20 degrees F.
Mums can be started from new plants, divisions from old ones, rooted cuttings, or seeds.
Chrysanthemum plants, unless reset annually, seldom produce as good a crop the second year as they did the first; they become too crowded. This crowding condition is caused by the production of underground suckers. These suckers make excellent divisions for spring propagation.
The best time to dig, divide, and replant is 3 to 4 weeks after the last killing frost in spring or after considerable new growth has been developed. A planting spacing of 18 to 24 inches is recommended.
The best time for new plantings is late spring when peonies and iris are in bloom – usually mid-May. Dana and Lerner said that fall planting has not proven very satisfactory throughout most of Indiana, although some container-grown plants may overwinter with adequate winter mulch.
In order to have sturdy, well-branched plants, it is advisable to remove terminal shoots once or twice during early growth by pinching or removing ½-1” of the stem back to a leaf. This should be done when the plant is 6 inches tall, about mid-June. When lateral branches become 6-8 inches long by mid-July, pinch those tips to induce even more branching. The procedure may seem drastic, but the results will be bushy, well-shaped, flowering plants.
Consider growing garden mums for yourself or adding some fall accents by purchasing containerized plants at your favorite local garden center.
For more information, access Dana and Lerner’s publication on chrysanthemums at: www.edustore.purdue.edu.