Mums — How to grow and keep chrysanthemums blooming!

Just when most other flowers are fading with the shortening days and cooler temps, and you almost have to give up on anything blooming, mums arrive! Every year, I think “thank goodness!” Chrysanthemums are stellar heralds of fall and, for me, they make summer’s end sweeter. I tend to buy lots of them — for the front and side steps, porch, stone wall, and driveway  — when the bright summer annuals are past their prime. I’ve even purchased them twice, once the minute they appeared at the garden center and again when that first batch was finished blooming. Happily, there are hundreds of types of chrysanthemums, including those with daisy-like petals, cushion-shaped flowers, flattened flowers and tube-shaped petals. Color coordinating them is always fun!

I’m hoping to keep my mums longer this year, coaxing them to bloom until frost. Or nearly frost, anyway. Here’s how.

Buy mums that haven’t reached their full potential yet

When you buy a pot of mums, consider not choosing the prettiest one, the one in fullest bloom (though these are admittedly almost impossible to resist!). The growers and sellers schedule them to be most appealing when you shop, but that means they’ll be past their prime sooner than ones just budding, too. Pick a plant that still has plenty of unopened buds so you have something to look forward to! 

green mums in a vase

Don’t overdo sun or heat

Mums love the sun, and you can place them in full sun if you’re ready for full blooms. If you want to slow the blooming down, though, locate them in indirect or slightly filtered sun. If you have a potted mum indoors, it will thrive in a sunny south window. If you want to slow it down, filter the sun with a sheer curtain. 

Similarly, they’ll bloom more quickly in the heat. So if you want them to last longer, avoid subjecting them to scorching temps.

Water carefully

Keep the soil moist but not wet. Don’t let them dry out. If the leaves are droopy, you’ve waited too long to water the plant. 

Water mums at the base of the plant, right into the soil rather than over the top of the leaves. Otherwise the leaves and blooms, which are susceptible to mildew, may brown.

Make sure potted mums have good drainage. Sometimes I transplant just-purchased mums into new (slightly larger) pots. But, if I’m not repotting them, I like to plop the pots they came in inside larger ceramic or terra cotta pots. If the outside pot doesn’t have drainage, be sure to pour out excess water after watering the plant. 

Fertilize

Fertilize potted mums every week or two during blooming season. 

Should I deadhead mums?

It’s a bit tedious, but yes, deadheading mums will encourage them to bloom again. Simply cut off the blooms by cutting the stems diagonally right above the next set of leaves below the flower. Don’t pull off the flowers; use your garden scissors. Cut off blooms as soon as they start fading. That way your plant will put energy into those buds rather than the fading flowers.

pink and red mums

Should I repot my mum plant?

It’s a good idea. After sitting at the garden center, it will probably appreciate new soil. It may even be rootbound (which keeps it from absorbing water very well). Repot into a container that’s a bit larger than its current pot, and use a good-quality potting soil. Loosen the roots when repotting. 

If you don’t repot (I don’t always find the time), check to see if the soil is overly dry. (It may have shrunk in from the sides of the pot, resulting in the water running alongside rather than through the soil — something especially common in late-season bargain purchases.) If the soil is super dry, soak the entire pot in a pail of water for a few hours until it’s thoroughly moist. Remove and water normally from then on. 

Planting mums as perennials

I must admit that here in Iowa I’ve had spotty luck planting mums in the ground. In an effort to make my mums last season to season, when my potted mums were finished blooming in the fall I’d often carefully plant and mulch them in the ground. Some survived, but they were hilariously puny plants come spring. Turns out, there are special varieties that are hardy perennials. These bloom for as long as a month in early fall. 

Here are some planting tips:

• Choose a hardy, perennial variety of mums.

• Plant either early in the spring, after danger of frost, or in the early fall. The key is to give the roots time to establish themselves before either frost or scorching weather. 

• Pick a spot where the plant will get full morning sun. (It needs a minimum of six hours of sun a day to bloom well.)

• Provide fertile, well-drained soil that is slightly acidic (a pH of about 6.5 is ideal).

• Plant the mum the same depth that the plant was in its pot. If you’re planting more than one, space them about 1 ½ to 2 feet apart. 

budding red chrysanthemums

• Once your mum starts growing in the spring, cut it back so that you wind up with a bushy, fuller plant. This is the hardest part for me, but it’s important! Pinch the plant a few more times over the early summer weeks,  but don’t pinch it past mid-July, or you may not give the plant enough time to produce buds and bloom.  

• During the growing season, fertilize your in-the-ground mum every couple of weeks. 

• In the fall, mulch the mum plant to protect it from winter temps. I like to cut mine back to about 6 inches, too. 

Remember to water your planted perennial mums in the spring. In fact, give them more water as the summer temps rise. At blooming time, a few weekly waterings in dry weather isn’t too much.

Overwintering Potted Mums

It’s possible to overwinter any mum in its pot, though hardy mums will handle this best. When the first frost arrives, simply cut the plant back to just a couple of inches in height. Place the pot indoors in a cool place, such as an unfinished basement or cool attic. (A temp of between 32 and 50 degrees F is perfect.) Water lightly over the winter months — just so that it’s slightly moist. 

In the spring, acclimate your mum by moving the pot outdoors for a few hours each day. Bring it back inside at night. After the frost-free date, you can let your mum pot vacation outdoors for the rest of the season. 

Propagating Mums

Division. I’ve never had an in-the-ground mum plant do well enough to divide (maybe after this year, when I plant a hardy perennial!), but apparently it’s easy to do — and mums like to be divided. Simply dig up your full plant in the spring and carefully pull it apart. Discard any less-than-healthy-looking parts of the plant and replant the sections. 

cut pink chrysanthemums on a wood table beside a plate

Cuttings. You can also start new mum plants from cuttings. Cut a stem about four inches long and remove the bottom leaves (leave just a few leaves on the top). Dip the stem in rooting hormone, then plant in vermiculite or sand. Cover with a plastic bag and place in bright light. Keep the potting mixture moist. When the stem has produced strong roots, pot it in a small pot until it’s big enough to transplant outside, if that’s your intent. (You could also do this with mums that you’re keeping in pots, hardy or not.)

Seeds. You can plant mums from seed, too, either indoors over the winter months (under lights) or by sewing the seed outdoors in the summer. Sew the seeds at least a couple of months before frost is due, to give them time to establish — this is an easy but long-term project! 

Have you ever seen cascading mums? Growers carefully propagate cuttings and grow them downward into long trailing cascades. Look at these gorgeous cascading mums at the Bellingrath Gardens in Alabama. 

What are your favorite types of mums? Have you had luck planting them in the ground? Keeping them blooming? Share your tips!

You might also enjoy:

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Storing bulbs for winter

How to care for orchids

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