Mums are for sunny places. They like a soil that has an abundance of organic matter, so work in plenty of peat moss or compost. Rooting is fairly shallow, so soil preparation need be only 10 to 12 inches deep. Surface and subsurface drainage must be good all year with no standing water or soggy soil at the crown, but a consistent supply of water is needed throughout hot weather. Apply the approximate equal of ½-1” of rainfall if nature doesn’t provide. Take care not to leave the foliage wet overnight.
Mums can be planted any time they are available, but stand the best chance of survival if they’re put in the ground early (when the soil is not colder than 40°) so roots can establish themselves. Mums are rapid growers and heavy feeders. Dig a hole at least 1½ times bigger than the root ball. Fill the hole around the plant with enriched soil and compost so the plant is exactly the same level it was in the pot. Use a root stimulating transplant solution like “Upstart” to help get your plants well established. Water well at least twice a week till frost time, but don’t fertilize or cut back the plant for now.
In the late fall…
cut the plants back close to the ground and discard the trimmings. Mulch your plant with a 6” cover of straw or shredded bark. Tree leaves can mat down and smother the crown of your plants, so avoid them as mulch. Secure the straw mulch with string, burlap, or a nylon mesh. Bark mulch is heavy enough not to blow away.
In the spring…
remove the mulch as the ground begins to thaw, clean up any debris, and work a moderate amount of bone meal and composted manure into the top inch of soil. Pinching back the growth tips encourages bushy, compact growth. This causes them to branch. Pinch the growth tips every 10 to 14 days until the middle of July. Pinching too late can cause loss of bud set. Not pinching will result in very uneven blooming in the summer and poor fall color.
Removing all but the center bud on each growing shoot produces big showy blooms. This is called “dis-budding”. Dis-budding is done when the buds are about the size of the head of a hatpin. The energy of the plant is then concentrated in the remaining buds.
Mum plants should be dug and divided every 2nd or 3rd spring to maintain vigor. Replant only the healthy portions of the original clump and discard the old woody growth.
Enjoy your Fall Mums! 🍂