– Christine Gelley, Agriculture and Natural Resources Educator, Noble County OSU Extension
Now that September is here, many people are shopping for fall mums to add to their seasonal décor. While many folks consider chrysanthemums annual plants that you buy and then throw away before winter, they are actually hardy perennial flowers that can be kept over in the garden for a period of about three years before it is recommended to rotate to another plant to reduce the pressures of insects and disease. If you are up for a little extra work to keep your chrysanthemums thriving in the garden, you may be pleasantly surprised to see them come back next growing season.
Mums can be planted essentially anytime from the beginning of spring to six weeks before frost as long as soil conditions offer enough moisture and fertility for good growth. Chrysanthemums can be started from seed, cuttings, or purchased in pots and transplanted. However, potted mums that are already flowering will likely not survive through the winter because energy allocation will primarily be to the flowers rather than root development. If you want to overwinter potted mums, buy mums that have not formed flower buds yet.
Mums will perform drastically better if they are removed from the pots they are purchased in and transplanted into the garden bed or a larger decorative pot. This will allow the roots to expand and make them more tolerant of environmental stresses. Mums need six or more hours of sunshine each day, regularly watered, loose textured and well drained soil, and good air circulation. Plant mums 18-30 inches apart. Good airflow will reduce issues with pathogens, pests, and fungi.
The flowering period can be extended if the plants are deadheaded (spent flowers removed) and a bushy growth habit can be enhanced by pinching or cutting back stems. Pinching should occur when mums are six inches tall and again at twelve inches tall and 100 days prior to the desired flowering period.
Although frost will kill the leafy tissue of the mums, the root ball should survive winter in the soil. You can cut the dead foliage off of the plant prior to winter. Mulched mums will cope with the moisture and cold weather that winter brings than those that are not mulched.
Of course, you don’t have to keep your mums overwinter. If having mums in a pot on your porch step for a month is satisfying to you, continue to support your local flower growers, distributors, and community fundraisers by buying as many mums in as many colors as makes you happy. No one will be sad to see you come back year after year for more. Make sure that your potted mums don’t get too dry by doing the finger test every day. Touch the top of the soil and if it feels dry, water until water flows out of the drain holes. If the soil surface feels damp, don’t water. Chrysanthemums can be composted. If you choose to reuse pots from faded mums, sanitize them before their next use.