When fall arrives, it’s hard not to regret the passing of all the summer blooms we love so much: pompon dahlias, Shasta daisies, African daisies, little zinnias, asters, coreopsis, and calendulas.
But take heart, for the fall garden offers all these flower shapes from just one plant, the chrysanthemum. Hundreds of hardy cultivars provide an array of colors and bloom shapes, making mums the divas of the autumn garden. The blooms last for weeks, not days, and the sheer number of flowers per plant will convince anyone that this flower really likes to show off. Add the mum’s impressionistic abilities to its longevity, and you have a plant that pulls its weight in the garden.
Because of their tight, mounded habit and stunning bloom cover, garden mums are perfect for mass plantings. To get the maximum effect from far away, stick to only one or two colors. Another possibility is to arrange a gradual transition of related colors. Look around your yard to see what colors would best complement the existing landscape.
If you decorate for fall with pumpkins and gourds, choose orange, bronze, yellow, and creamy white mums. If you have a lot of evergreen plants that provide a backdrop of varying shades of green foliage, try bright pinks, lavenders, pure whites, or reds. With such bold colors, a large grouping of mums can excite even the most drab of fall landscapes.
Garden mums also make great container plants. They’re just right for popping into a clay pot, lining up in a row in a window box, or placing in the center of a mixed container with trailing foliage plants all around. Many landscape plants can provide a backdrop for groupings of mums. For texture, choose ornamental grasses or the neon purple berries of the beautyberry shrub (Callicarpa). You also can pair mums with smoke tree (Cotinus), variegated sedum, the deciduous dwarf Fothergilla gardenii, or almost any conifer.
To get the most from your mums, choose cultivars according to their bloom times. It also helps to coordinate bloom time with the length of fall in your location. Most garden mums will withstand a light fall frost, but finding the right cultivars will provide the longest possible amount of pleasure.
Location. Choose a spot 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 yard is soggy after the slightest rain, grow 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 for best performance. Mums’ 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.
Trim off the previous year’s stems as soon as the new spring growth begins to show.
Watering. Water newly planted mums thoroughly, and never let them wilt. After they are established, give mums about an inch of water per week. When bottom leaves look limp or start to turn brown, water more often. Avoid soaking the foliage, which encourages disease.
Fertilizer. Plants set out in spring should get a 5-10-10 fertilizer once or twice a month until cooler weather sets in. Don’t fertilize plants set out in fall as annuals, but plants you hope to overwinter should get high-phosphorus fertilizer to stimulate root growth.
Overwintering. Prepare mums for winter after the first hard frost. Mulch up to 4 inches with straw or shredded hardwood. Fill in around the entire plant, spreading well between 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.
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 keep 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, they have already been pinched and are ready for planting. Young spring plants will need pinching for maximum bloom and best plant shape.
Start pinching as soon as you see a good flush of buds. Pinch about half of the tender new growth at the top of the shoot; choose some stems with buds and some without. Repeat the process with every 3 to 5 inches of growth (about every two to four weeks) until July 4. Stopping then ensures you will get good bud formation and blooms in fall.
Annual or Perennial?
Mums aren’t as expensive as many perennials, so if you choose to, you can plant them as annuals without worrying that you’ve spent too much money on something that might not live more than one season. If you’re an impulse buyer, you’ll probably see pots of colorful mums this fall and not be able to resist.
Fall planting lessens the chance of winter survival, however, since roots don’t have time to establish themselves. If you want something more permanent and are willing to provide proper care such as mulching and pinching to encourage compact growth and more blooms, plant mums in the spring and allow them to get established in the garden. This will improve their chances of overwintering and reblooming the next year. Some plants will even produce a few blooms in the spring before being pinched for fall flowers.