How to Deadhead Mums to Keep the Blooms Coming
Chrysanthemums, full of glory in autumnal tones, benefit from easy deadheading for a lasting show of color. With gardening expert Katherine Rowe, explore the benefits and basics of removing faded blooms to extend flowering and develop strong roots for in-ground selections.
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Whether growing hardy chrysanthemums as garden perennials or enjoying them as nursery potted seasonals, removing faded flowers heightens and extends their colorful show. Mums are robust bloomers, setting their buds early to mature and burst into color for weeks in late summer and fall.
Easy-care mums don’t require much maintenance to thrive in the border or containers. With regular moisture, sunlight, well-draining soil, and deadheading, garden mums bloom until heavy frost. Year-round growers have soft, mounding foliage with loads of blooms after a couple of sweeps of easy, early-season pruning.
Benefits of Deadheading Mums
Deadheading directs energy to remaining buds and flowers, keeping color going through frost. It’s particularly helpful for developing sturdy roots. It further benefits the robust bloomers by:
- Directing energy to existing, unopened buds
- Exposing hidden or concealed buds along the stem
- Promoting continued flowering and root development rather than seed production
- Tidying the look of the display
Deadheading mums, while not essential to growth, is a common practice to support remaining flowering and tidy up the plant’s appearance. Removing spent blooms is one of the simplest ways to encourage a long-lasting season while retaining the best form. Aged flowers wilt and brown on the stem; removing them refreshes the look in full color.
Chrysanthemum Flowering
Chrysanthemums set all their buds in early to mid-summer. As the plant grows, the buds develop and open as temperatures mellow and daylength shortens. For mums, clipping off the faded flowers doesn’t promote new buds.
It prevents plants from going to seed; instead, they channel the energy into present flowering and root development. More energy in root growth, rather than reproduction through seed, enhances winter survivability. Hardy mums bring years of lasting color and are worthwhile perennial additions. They last beyond the potted display in exciting forms and colors.
When and How to Deadhead Mums
Peak flowering season in late summer and fall may warrant deadheading two or three times a week. A single sweep done frequently makes the process quick and easy.
Remove spent flowers when they begin to wither and lose their color. Try to catch them before they turn brown and dry, which means seed production is underway.
Cut or pinch off a single flower as it fades. Pinch the stem between your fingertips or use snips for easy removal. Cut stems back to a healthy set of leaves, sometimes clipping a couple of inches to remove the bare stem that held the blossom. Leaves and buds conceal the fresh cut.
Pruning Perennial Mums
Hardy chrysanthemums shine with seasons of autumnal color as perennials in USDA zones 5-9. Pruning these hardy mums keeps branches from getting long and leggy or flopping over. It maintains their mounded, leafy form and promotes uniform budding.
A light prune for the quick-growers is pinching back the stems during their early season growth spurt. Wherever you pinch or trim, new growth develops. Pinching differs from deadheading (even if you pinch off the blooms). It serves to direct growth during the vegetative phase.
Routine trimming and pinching:
- Improves form and growth habit
- Increases airflow and light exposure among stems and leaves
- Encourages new growth and promotes flowering
- Rids the plant of crossing, weak, or dead branches
- Reduces pest and disease spread
- Fosters strong roots for successful overwintering
When to Prune
Nursery potted specimens are display-ready and shaped for our autumnal arrangements. There isn’t a need to pinch or prune newly purchased potted mums unless you discover broken stems. Looking ahead for your hardy in-ground selections, plan two to three rounds of pinching in spring and early summer to foster the best development.
First Round in Spring
When growing in the ground, spring is the time to initiate pruning. Established and new plantings benefit from pinching as they put on new growth. For new plants, begin pinching about two weeks after planting.
Pinching new growth at various phases of development creates healthy, full forms and all-over flowering. This light pruning creates compact, sturdy stems for consistent budding and blooming.
When stems reach about eight inches tall, begin pinching them back, and do so every few weeks (with every five to six inches of new growth).
Final Pinch in Early Summer
Depending on the variety’s bloom time, pinching occurs through late June or early July before buds set. Pinching too late into the summer prevents buds from forming, resulting in fewer flowers. Buds need several weeks to fully develop for the autumn show.
Mid-July is usually the cutoff to stop pinching and foster healthy buds on your well-formed plants. Many gardeners use the Fourth of July to mark their final pinch.
Overwintering and Post-Bloom Care
With heavy frost, the herbaceous perennials enter winter dormancy. In cold climates, leave the dormant stems in place as insulating materials for the crown and roots. Wait until late winter/early spring to cut stems back before new growth emerges within a few inches of the soil level.
In lower growing zones, add extra mulch for cool-season protection. Use a light layer of mulch on crowns, or add evergreen boughs to protect against ice and frost heaving as soils freeze and thaw.
To overwinter mums in containers, place them in a cool, sheltered location like a garage or basement until the final frost passes in spring. Check the soil moisture level occasionally to keep roots from drying out completely.
Divide chrysanthemums every few years to expand the collection and renew vigor.
Frequently Asked Questions
What happens if you don’t deadhead?
Chrysanthemums don’t need deadheading to survive; they’ll bloom away without pruning or removing spent blooms. But, pinching off aged flowers redirects energy from seed production into the remaining buds and flowers during peak season. It also fosters root development for stronger, hardier perennials.
Should I cut them back in winter?
Leave mums standing for added winter protection. Their dormant foliage and stems insulate the crown and roots. Add mulch for insulation. Cut old growth back in late winter or early spring as temperatures warm to make way for new stems and leaves.
Can I plant my nursery-potted mum?
The best time to plant mums is in the fall or spring, and planting nursery mums late in the fall presents a risk of surviving winter since most of their energy goes into flowering rather than establishing roots. If your first frost is fast approaching or already occurred, but you want to preserve your potted mum, try overwintering the pot in a protected area like a cold frame, garage, or basement. Check it for water needs every few weeks to keep soil and roots from drying completely. Plant them outside or transplant to a larger pot in the spring.
If your frost is weeks away or you live in a frost-free climate, try planting the mums in the ground. Water them in, and add extra mulch like leaves, straw, or bark chips as added winter protection.
