growing hardy mums
soil and location
First off, mums must have excellent drainage. Wet soils, especially in winter, can lead to the demise of your beauties. Please avoid poorly drained locations. Work the soil to a depth of 8-12 inches and mix in 2-4 inches of compost. Mums do best in a sunny spot (6-8 hours) away from strong winter winds.
fertilizer
Feed plants with a 20-20-20 complete fertilizer every 7-10 days once plants are actively growing. Mix a tablespoon per gallon of water and apply to the soil around the plant. This feeds the plants while watering them. Continue this until early August. Or you can add a long-lasting granular fertilizer such as Osmocote (which we sell!) at the beginning of the growing season.
planting
Get them in the ground as soon as possible. Space according to their size with the taller varieties about 18-24” apart and the short compact plants about 12” apart. Dried stems/flowers act as a buffer during winter. Established plants can be divided every spring when 4” tall and after danger of frost. The stronger shoots are usually on the outside of the clump. Wait to cut back in spring as soon as new growth emerges.
pinching
True chrysanthemums* can be pinched in June to promote a bushy shape. Remove the tips of young shoots when 7-9 inches long. Remove any new shoots that occur after this first pinch when they are again 7-9 inches long. Continue until late June – early July. Pinching later than this can delay blooming, which you don’t want! Very high summer temperatures can also inhibit flowering. Removing spent flowers is a good tactic to promote more. *Some of our hardy “mums” are actually a related plant known as Dendranthema (look for ‘Igloo’ series on the tag). These do not need to be pruned during the summer like chrysanthemums.
winter care
Mulching and mounding plants goes a long way to preserving the root system as mums are sensitive creatures. After frost, place a few scoopfuls of soil 8 inches high around the base of the plants. Cut the branches back to 10 inches above the mounded soil line. Once the soil surface freezes, add 2-4 inches of mulch. Avoid using leaves as they pack solid when wet.