Garden mums provide us with a wide array of color and form in the fall. They are a perfect replacement for the annuals we have enjoyed since spring. Mums will provide a nice color display until freezing weather arrives. Most garden mums are sold in late summer and early fall as mature budded plants.
Pot-grown garden mums have most of their root system intact, but it has been confined to a relatively small area. It is a good practice to rough up the root ball after removing from the pot. This can be done with your hand or by using a knife to cut some vertical lines down the sides of the ball. This practice will promote some lateral branching of the root system into the surrounding soil. Continue to provide adequate water and fertilizer until a strong root system can develop. Mums are heavy feeders; you can use either 10-10-10 fertilizer or water-soluble fertilizer.
Chrysanthemums should be planted where they will receive as much sun as possible. Mature plants set in a shady situation will give nice color that fall, but do very poorly the following year. While mums require a lot of water, they should still be planted in soil that is well drained. Some type of organic matter, such as peat in sandy soils and maybe some sand in heavier soil situations. Mulching will help retain soil moisture, control weeds, and improve overall appearance.
Mums can withstand very cool temperatures and even light frosts. The first hard frost usually marks the end of the season for hardy mums. Once the plants are dormant, the tops should be removed, clean up old leaves and debris and re-mulch the area. New shoots will appear early the following spring. It is a good practice to divide mums at least every 2 years. Mums can be propagated by dividing off the new offset that form around the old crown. Remove these carefully with as much of their root system intact as possible. Transplant these into the area you want them to grow in or into pots for later placement. An alternative method of propagating your old plants is to make your own rooted cuttings. Each cutting should be 3-4″ in length. Remove all leaves from the bottom inch and stick the cutting into a rooting medium such as sand, perlite or vermiculite. Keep cuttings moist and out of the direct sun. Frequent misting during the first 3 or 4 days will help prevent wilting. The cuttings should be well rooted in 10-14 days. They can be planted directly in the ground or into pots for later planting. Chrysanthemums planted or propagated in the spring require repeated pinching to create nice, low, bushy plants for fall. Pinch back all new tip growth every 2-3 weeks starting when the plants are 6″ tall and continue until July 1-15.