Key Takeaways
Pruning mums helps them grow fuller with longer-lasting blooms.Pinch tips at 4–6 inches tall, again at 12 inches tall, and stop about 100 days before bloom.Deadhead spent flowers once blooming begins to encourage reblooming.
Chrysanthemums are as welcome and colorful a sign of fall as cheery orange pumpkins. These autumn-blooming perennials come in a wide variety of hues, and they’ll reward you with clusters of tiny flowers until the first frost.
Mums are often sold as annuals, but it’s possible to overwinter the plants, even in cold climates, and regrow them again the following spring.
But to do that—and get those dome-like masses of blooms—it’s important to prune them properly and at the right time. Here’s when and how to prune mums for beautiful, long-lasting fall color.
The Best Time to Prune Mums
The best time to prune mums to encourage fuller fall blooms is in springtime, once plants have reached between 4 to 6 inches tall.
Plan to prune mums again when plants have reached 12 inches tall, then once more about 100 days before you’d like your plants to bloom.
That can be as early as mid-September, depending on your region’s climate. This pruning technique, in which young growth tips are removed to create bushier lateral growth from stems, is called pinching.
Overwintered mums should be cut back to 3-4 inches tall in early spring, before new leaf growth or buds have formed. Remove any dry, dead growth from the previous year when you do this hard pruning.
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How to Prune Mums Without Ruining Your Plant
Once young chrysanthemum plants have reached 4 to 6 inches tall in spring, use your fingers or a set of pruners to remove the last three-quarters of an inch from each stem. Remove newly formed flower buds down to the first set of leaves. Prune mums a second time when plants have reached about 12 inches tall, using the same technique with your fingers or pruners.Finally, pinch back chrysanthemum plants one more time about 100 days—or a little over 3 months—before you’d like to see fall blooms.After overwintering mums, cut back plants to about 3 or 4 inches tall in early spring to encourage new growth.
Mum Pruning Tips
To determine the approximate bloom time for your mums, look for the designations “early season” or “late season” when purchasing plants at nurseries and garden centers. If you’re buying plants in full bloom in early fall, they’re likely early season, while late-season varieties may still be in bud at this time of year.
Use clean hands or a set of clean, sterilized shears or pruners when pinching back mums to avoid spreading plant diseases.
After your mums begin blooming, pinch or trim off spent blooms as they appear. By deadheading the plants, you can encourage more flowers and prolong bloom time.
In milder climates, in-ground mums may be able to survive the winter. In colder climates, plant mums in containers, then overwinter them in a shed, garage, or enclosed porch to regrow them the following year.
FAQ
Is pinching better than pruning for mums?
Perennial mums require both pruning and pinching to thrive and offer abundant blooms in fall. Bloom time depends on whether the mums you’re growing are early season or late season.
Can I prune mums in fall or should I wait until spring?
Wait until spring to do a hard pruning on perennial mums. Pinching mums should take place in spring and summer.
How do I keep mums bushy and blooming longer?
Set your mums up for a long, full bloom period by pinching them back as described. Remove spent flowers as they appear to encourage regrowth and extend your chrysanthemums’ bloom period.
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