Mum Care 101: Planting, Blooming, and Overwintering Tips
Move over, pumpkin spice—autumn’s true star is the chrysanthemum. Known affectionately as “mums,” these jewel-toned beauties transform gardens and porches into dazzling displays of fall color. But mums aren’t just one-season wonders. With the right care, they’ll return year after year, bigger and brighter than before. Ready to master the art of mum-growing? Let’s dig in.
Chrysanthemum x morifolium (formerly Dendranthema x grandiflora) is the Queen of the Fall Flowers, celebrating the season in jewel colors: yellow, lavender, pink, purple, red, bronze, orange, and white. Each bloom consists of tiny flowers called florets. Bloom forms range in size from pincushion petite to giant spiders, and there are hundreds to choose from.
Mums generally reach a width and height of 3 feet if they are pinched regularly during the growing season. Bloom time is determined by day length (12 hours or less!), and buds start forming then. Mums spread quickly if properly planted and spaced.
Are Mums Perennial or Annual?
Mums are hardy perennials best planted in early spring. However, those pretty mums sold in garden centers as fall decorations are often best treated as annuals; do not try to overwinter them, as they weren’t bred to be hardy.
Do Mums Come Back Every Year?
Yes, if you plant a cold-hardy perennial that’s marked to withstand low temperatures, it will come back every year. Early spring is the best time to order and plant mums to give them time to grow strong roots, become well-established before winter, and grow into a more robust, full plant.
Southerners can enjoy the colorful displays of blooming mums twice yearly because the equal days and nights of temperate weather that cause mums to bloom happen in both the spring and the fall. Northerners must be satisfied with one show in autumn.
Credit: Catherine Boeckmann
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Planting
Select a planting site in full sun, away from trees and big shrubs. Mums require rich, well-draining soil. They do not like standing water and will quickly rot if left too wet. Prepare by adding aged manure or compost to the soil (mums are heavy feeders).
Container Tip: Many folks will set their potted mums on or near their porches. Plants that receive light at night from security lights or street lights will be slow to bud! If you’re wondering why your mum isn’t blooming, it’s often due to this reason (as well as lack of sun or water).
When to Plant Mums
- Mums are hardy perennials best planted in early spring.
- Start mums indoors from seed 6 to 8 weeks before the last spring frost date.
How to Plant Mums
- Set mums 18 to 36 inches apart, depending on their expected size at maturity.
- Mums need good air circulation.
- Plant mums in the ground at the same depth that it was grown at in the pot. Water can gather around the base and rot the stems if planted too low.
- Water and keep it evenly moist.
- If you are growing mums in pots, they will be dry in no time, and you must keep them moist; when you water, it should drain out the bottom. (If you buy mums in wrapped containers, make sure they have drainage holes!)
Growing
- Watering mums is vital to success; too little water slows or stops their growth! Keep mums moist. Soak the soil deeply when watering. Avoid watering the leaves.
- Mums are heavy feeders. A monthly application of a balanced fertilizer (10-10-10) is good practice.
- Spread mulch around the mum to conserve soil moisture and to keep weeds out.
- Pinch back stems to create a bushier plant: When new shoots are 3 to 4 inches tall, pinch off the top, leaving 2 to 3 leaves on the shoot. Continue pinching every 2 to 3 weeks until mid-July, when buds develop. On the West Coast, stop pinching in early July. In the South, stop in early August.
- Stop fertilizing when flower buds emerge.
- For big flowers, pinch off all buds except the largest and strongest on each stem. Remove secondary buds farther down the stem as they develop, too.
- Switch to a high-nitrogen fertilizer after the buds have set. If flower size does not matter, stop fertilizing in mid-August.
- After the ground has frozen, spread 4 to 6 inches of mulch around the plant.
- Do not cut back mums in the fall. The dead growth insulates the roots. Cut off the dead stems and leaves when you see the first green shoots in spring.
Overwintering Mums
Hardy to USDA Zones 5 and warmer, perennial chrysanthemums can be kept outdoors (in the ground) through the winter. But in extremely cold areas, overwinter plants in a basement or dark, cold closet. Pot up plants after the first frost in the fall, capturing as many of the roots as possible. Leave the foliage on the plants until spring.
Water well and keep the roots damp. Check pots weekly. In spring, gradually introduce the plants to light. Set them out after the last killing frost.
Dividing Mums
Every 2 to 3 years, divide mums when new growth appears in the spring. Use a knife to cut out the old central portion of the plant. Discard it. Cut the remaining portion into sections. Each section should have several shoots and good roots. Replant these sections.
Types
Mums belong to one of 13 classes based on flower form and petal shape!
- Irregular Incurve: giant blooms, e.g., ‘Bola de Oro’ (gold)
- Reflect: very large to medium blooms, e.g., ‘Pretty Polly’ (purple, with pink reverses)
- Regular Incurve: ball-shaped, e.g., ‘George Couchman’ (bronze)
- Decorative: flattened, e.g., ‘Coral Charm’ (salmon)
- Intermediate Incurve: more open than other incurves, e.g., ‘St. Tropez’ (crimson, with bronze reverse)
- Pom Pom: balls, e.g., ‘Kevin Mandarin’ (deep orange)
- Single and Semidouble: concave/convex, e.g., ‘Domingo’ (crimson, with yellow center)
- Anemone: single, e.g., ‘Daybreak’ (apricot, with yellow center)
- Spoon: single/daisy with tipped ends, e.g., ‘Kimie’ (yellow, with green center)
- Quill: tubular florets, e.g., ‘King’s Delight’ (true pink)
- Spider: varying florets, e.g., ‘Lava’ (yellow, with red tips)
- Brush or Thistle: upright florets, e.g., ‘Wisp of Pink’ (yellow center)
- Unclassified or Exotic: irregular, e.g., ‘Lone Star’ (pure white)
Extra-hardy Mums
These will survive in frigid climates: ‘Betty Lou’ Maxi Mum, ‘Burnt Copper’, ‘Centerpiece’, ‘Grape Glow’, ‘Lemonsota’, ‘Maroon Pride’, ‘Mellow Moon’, ‘Minnautumn’, ‘Minnpink’, ‘Minnruby’, ‘Minnwhite’, “Minnyellow’, ‘Rose Blush’, ‘Sesqui Centennial Sun’, ‘Snowscape’.
Credit: EdenGardenGr.
Harvesting
Cut chrysanthemum flowers for arrangements when they are nearly or fully open. Remove lower leaves that would be in the water. Leaves submerged in water will rot. Change the water in the vase every couple of days. Vase life is 7 to 10 days.
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