Choose a location that gets at least six hours of sun a day. Plants that don’t get enough sunlight will be tall and leggy and produce fewer, smaller flowers. Soil Preparation
Mums thrive in well-drained soil. Heavy clay soil should be amended. If your chosen location is soggy after the slightest rain, grow your mums in raised beds with friable soil for good root growth. If the soil is too dense, add compost and prepare to a depth of 8–12 inches. Gypsum or greensand can be added to loosen clay soils. Mum roots are shallow, and they don’t like competition. Plant mums about 1 inch deeper than they were in the nursery pot, being careful with the roots as you spread them.Watering
Water newly planted mums thoroughly, and never let them wilt. Use Schultz Starter Plus to stimulate new root growth. After they are established, give mums about an inch of water per week. If bottom leaves look limp or start to turn brown, water more often. Avoid soaking the foliage, which encourages disease.Fertilizer
Use a complete fertilizer such as Plant-Tone, Jack’s Classic All Purpose, Super Phosphate, or Osmocote, beginning in the spring when new growth appears. Follow the directions on the label as to frequency of application. Fertilize through August.Overwintering
Prepare mums for winter after the tops have turned brown. Mulch up to 4 inches with straw or shredded hardwood. Fill in around the entire plant, spreading well between the branches. Pinch off dead blooms to clean up the plant but leave branches intact. Mums have a better chance of surviving if you wait to prune old stems until spring. As soon as the weather warms, pull away mulch to allow new shoots to pop up.Dividing
Mums grown as perennials need to be divided every couple of years. Divide in the spring after the last hard frost and after you see new growth starting. Dig up the plant in one piece and separate outer pieces from the center with a clean, sharp spade or large knife. Replant the outer portions into a rejuvenated bed, and discard the original center of the plant.Pests
You may notice aphids, leafhoppers, or spider mites, but they are not likely to harm the plant. Treat with an appropriate insecticide.Pinching Mums for Better Bloom
The key to those full, rounded domes of blooms that you associate with mums is pinching to create more branching and keeping plants compact. Don’t hold back; just a few minutes here and there will reward you with a thick, solid-looking plant. If you’ve bought large, full plants in the fall, then they have already been pinched, and you don’t need to do anything except plant them. Young spring plants will need pinching for maximum bloom and best plant shape. In spring, start pinching as soon as you see a good flush of growth. Pinch about 1 inch of tender new growth at the top of the shoot. Repeat the process with every 3–5” of growth (about every two to four weeks) until July 4th. Stopping then ensures you will get good bud formation and blooms in the fall.