How to Plant Hardy Mums Outdoors as Year-Round Perennials

Planting Potted Mums in the Fall

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Can I plant chrysanthemums outside?

Yes, but. Here’s some things to know first so your expectations are realistic.

Those chrysanthemums (mums) we see at grocery stores in fall—and some in spring—are not all created equal: there are dozens of mum species and thousands of varieties!

Even when they are sold as ‘hardy’, it may not mean winter hardy. Often it just means they can tolerate some light frosts before dying.

In general, mums can be hardy in zones 4 to 9, but the colder your hardiness zone, the less likely they are to survive winter conditions.

If you want better odds, your best bet is to track down a plant nursery that has successfully tested specific varieties in your winters. Mammoth mums are a well-known group of hardy mums sold to northern areas.

If you want to gamble with grocery store mums of unknown hardiness—and why not if you have room to experiment?—your best bet is to overwinter them in their containers in a protected space (above freezing, never letting the soil dry out). Then, you can plant them in spring, providing lots of time to establish strong roots before their first winter in the ground.

If you just want to try planting them in fall and see what happens, I’ve listed the steps below.

Mum Hardiness Tests

• University of Minnesota | zones 3-4 | “Showy perennials that flower from August until frost, these U of M mums are uniquely developed to withstand USDA Zone 3 and 4 growing conditions and will usually overwinter when covered with a protective mulch in late fall. Mums prefer full sun and well-drained soil.”
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• University of Vermont Extension Department of Plant and Soil Science | zone 4  | “… in research trials at the University of Vermont Horticultural Research Center in S. Burlington, of the 80 varieties trialled over a period of four years, none was found to be reliably hardy for the Burlington area, one of the milder areas of the state. Lack of a good snow cover affected the plants’ survival rate. Many of these same varieties would probably do well in areas that receive heavier snowfalls.”

Tips for Growing Mums as Perennials

These tips are for fall planting.

1   Choose healthy potted chrysanthemums with no sign of wilt or browning. Ideally, they are budding but not yet blooming. They must be winter hardy.

2   Mums will not tolerate dry soil (they’ll die) so stay on top of the watering from the moment you get them. If it’s hard to check the soil, a moisture meter will do the job nicely.

3   It’s ideal to plant your mums at least 6-8 weeks before fall frosts to allow time for roots to establish.

4.  When ready to plant, first, snip off the buds or flowers so the plant puts its energy into root production. Yes, I’m saying to cut off the blooms. It’s for the best. 

5   Choose a full sun location (6 hours of sun per day) with well-draining soil. As much as they can’t tolerate dry soil, neither will they tolerate soggy soil.

If planting several, allow 18-inches between plants.

6  Hold off fertilizing until spring.

7   Water deeply, and continue watering right up until frosts begin.

8  Set aside several inches of mulch (compost, ground-up leaves, bark, or straw) to place around the plant after the ground freezes. Snow is also an excellent insulator.

9  Resume watering in spring. Check if ‘pinching back’ is recommended for your variety to encourage blooms in fall.

Growing Mums from Cuttings

You can also try propagating your mums. The steps are the same as shown here with hydrangea cuttings.

1. Take a new, green cutting with several sets of leaves, cutting just below a set of leaves.
2. Remove any flowers.
3. Remove lower leaves, keep top leaves.
4. Dip base of stem in rooting hormone and plant in moist potting mix.
5. Place inside clear tub or cover with large clear bag to retain humidity.
6. Ensure even moisture.
7. Keep above freezing in winter (they will be dormant). Growth will resume when temperatures warm in spring.

If you try planting your mums in the ground, I want to hear how it goes. As said, unless you know you’re getting a proven hardy variety, it’s a gamble. But, if you’re just going to toss them anyway, it could be worth overwintering them or planting them in the ground.

~Melissa the Empress of Dirt ♛

Next

• How to Grow Hydrangeas from Cuttings
• How to Grow Clematis from Cuttings
• Beginners Guide to Basic Plant Propagation