Chrysanthemum means "golden flower", from the greek chryos, meaning gold and anthos, meaning flower. Mums, as we often refer to them, are related to the daisy. When you ask a child to draw a flower they inherently draw a daisy. Even when we are young we are in love with this flower. It seems without thinking we have made a great choice as the mum comes in a multitude of colors and styles.
Mums are often grouped as hardy, garden, florist or annual, terms that people often find confusing and rightly so. Two types of mums that are divided into these groups are Chrysanthemum x morifolium and Chrysanthemum X koreanum. These can be separated into many different growth forms. Some of these include daisy, quilled, decorative, pompon, cascade and spider. Florists often use pompon, daisy and spider mums and these are usually kept until the blooms fade and then tossed out. Mums planted outdoors in commercial settings are often planted as annuals with the idea that they will be removed before spring to allow for pansies or some other spring blooming annual. Although cultivar does play a role, in our area the hardiness of the mum can be attributed to both the climate for the year and whether the plant had enough time to establish a good root system.
The common size of the Mum is 1 to 3 feet which can be reached easily by feeding and watering generously. The shape of these plants can be improved by cutting or pinching new growth. Start pinching hardy mums once they have come up and reached between 5 and 8 inches of growth. Continue pinching each time 4 inches of new growth develops, pinching the tips back ? inch each time. A good rule of thumb is to stop pinching on the 4th of July. This provides an easy date to remember and allows plants enough time to develop buds for flowering in the fall. Through manual pinching, your plants will form a nicely rounded and full bushy appearance with many flowers.
Mums bloom based on day length. When days get shorter, or more correctly, when nights get longer, flowers will initiate. Mums require between 9.5 and 10 hours of darkness to bloom. This requirement usually gives us blooms between Mid-September and Mid-October each year. If you plant mums underneath street lights you may find that they do not bloom as expected as the light will interfere with the required 'dark' period.
Mums are a low maintenance plant that needs only full sun and spring fertilizer to provide delightful color; however, mums do have pest issues. One of the largest pests for mums is aphids. Mites, thrips and leafminer are also found in high numbers on plants. If an insect population becomes high enough, it can reduce the vigor and health of the plant. Often, sufficient spacing will help reduce pest populations early on and cold weather will help after bloom.
Common disease issues include root rot, wilt, blight and leaf spot. The best way to prevent these diseases is to space mums far enough apart that leaves will not touch at maturity, allowing them to get as much air circulation as possible. A well drained soil will help prevent root rots. By watering in the morning, if at all, you will help prevent leaf diseases.
Don't be afraid to try out a new color and plant it outdoors to see if it will come back. The earlier you get it in the ground, the better your chances of seeing that plant again next year.
Helpful Sources: Still, Steven M. Manual of Herbaceous Ornamental Plants. 1994. Stipes Publishing. Champaign, Ill; Chrysanthemums for the Home Garden. Kemper Fact Sheet. Missouri Botanical Garden, 2001-2009. http://www.mobot.org/gardeninghelp/plant...
The Extension office is located in Kennett, Missouri at 101 South Main Street (the old bank) on the 2nd floor. Open Monday -- Friday or you can call 573-888-4722 if you have a question. University of Missouri Extension programs are open to all.
Sarah Denkler is a horticulture specialist
with University of Missouri Extension
in Dunklin County.