How To Overwinter Chrysanthemums: Cold-Hardy Survival Hacks for Next Year’s Blooms

How to overwinter chrysanthemums could save your plants—and even make them bloom even harder next spring. 🌿 The key is timing, location, and a few simple tricks that protect their roots while letting them rest. I’ve overwintered mums for years, and the ones I prep properly always bounce back with vibrant color by early summer.

Start by cutting back foliage to 3-4 inches once frost hits, then mulch heavily with straw or leaves. In colder zones (below 20°F), add extra insulation like burlap wraps or even a small frame covered with plastic.

Containers? Move them to a sheltered spot or garage before temps drop below 25°F.

By spring, you’ll see fresh growth pushing through the mulch—proof it worked. The plants won’t bloom until late summer, but they’ll be stronger, fuller, and ready to outshine last year’s display. Just watch for rot from soggy mulch or frost heave in containers.

Works for hardy varieties like ‘Hardy Bonanza’ or ‘Mammoth’—perfect for zones 5-9. Skip this for tropical mums (they’re not cold-tolerant). Here’s how to troubleshoot if stems turn mushy or flowers flop next season.

What you need

Step-by-Step instructions for overwintering mums

Here’s the foolproof method I’ve used for years to bring back those vibrant blooms every spring.

Start by choosing the healthiest chrysanthemum plants—look for stems with at least 3-4 strong leaves and no signs of disease or pest damage. Cut back the foliage by half, leaving about 2-3 inches of stem. This reduces water loss and helps the plant focus energy on root survival.

Gently dig up the plants, keeping as much root ball intact as possible. Shake off excess soil to check for rot or pests. If you spot any issues, trim affected roots with clean shears. The goal is to store only the strongest, most resilient plants—weak ones won’t make it through winter.

Place the dug-up plants in a shady, dry spot for 3-5 days to let the roots dry slightly. This prevents rot in storage. You’ll know they’re ready when the soil around the roots feels dry to the touch but the roots themselves aren’t brittle.

While curing, avoid watering—just let nature do its work. If your climate is humid, spread the plants out to improve airflow. The drying process is critical; damp roots will mold or rot in storage, and you’ll lose your entire batch overnight.

Wrap the roots of each plant in newspaper or bubble wrap to protect them, then place them in a cool, dark spot like a garage, basement, or even a refrigerator crisper drawer (if it’s not too cold). Aim for temperatures between 35-45°F—any warmer, and the roots may sprout prematurely.

Store the wrapped plants upright in a container with dry peat moss or vermiculite to absorb any moisture. Check them monthly to ensure no mold or rot has developed. If you notice any dampness, unwrap and let them air out for a day before rewrapping.

When spring arrives and nighttime temperatures stay above 50°F, it’s time to wake your mums from dormancy. Remove them from storage, trim any dead or mushy roots, and repot them in fresh potting mix with added compost for nutrients.

Water lightly at first, then gradually increase watering as new growth appears. Place them in bright, indirect light for the first week to avoid shock. You’ll see fresh green shoots within 2-3 weeks—that’s your signal everything worked. Once they’ve established new growth, you can move them outdoors after the last frost.

Tips & tricks for overwintering chrysanthemums

Real talk: Overwintering mums successfully comes down to a few key details that most gardeners overlook. Here's what nobody tells you—these small tweaks make all the difference between waking up to vibrant blooms or sad, wilted stems next spring.

Selection Matters: In Step 1, when you're choosing plants, focus on those with thick, woody stems—these are the ones that'll survive winter. Thin stems with hollow centers won't make it. Also, look for plants that have already started flowering—they're more established and better equipped to handle dormancy. The 3-4 leaves guideline is great, but prioritize stem thickness over leaf count if you have to choose.

The Cure is Critical: That 3-5 day drying period in Step 2 is non-negotiable. I learned this the hard way after losing an entire batch to rot in my basement. The roots need to be dry but not brittle—think of it like curing meat. If you're in a humid climate, consider spreading plants out on a screen or using a fan to circulate air. This prevents that dreaded mold that can wipe out your entire collection overnight.

Storage Temperature Secrets: The 35-45°F range in Step 3 is ideal, but here's the thing: your refrigerator's crisper drawer might be too cold (below 35°F) or too warm (above 45°F). Use an appliance thermometer to check—many fridges run hotter than you'd expect. If you don't have a garage or basement, a cool closet with good ventilation works surprisingly well. And remember, consistency is key—don't move plants between different temperature zones during storage.

Spring Revival Hack: When you're ready to revive your mums in Step 4, don't rush the watering. I've seen gardeners drown their plants by watering too soon after repotting. Instead, wait until you see tiny green buds at the base—this tells you the roots have started rehydrating properly. Then, water lightly but frequently, keeping the soil moist but not soggy during those first critical 2-3 weeks of regrowth.

Frequently asked questions

When is the best time to start overwintering chrysanthemums?

The ideal time to begin is before the first hard frost hits your area (typically late fall, around October or November). If you’re digging up potted plants, wait until temperatures consistently drop below 40°F (4°C) at night. For in-ground mums, cut back foliage after the first frost but leave the roots intact—this gives them time to harden off naturally.

Can I overwinter chrysanthemums in the ground, or do I need to dig them up?

It depends on your climate! In USDA Zones 7-10, many chrysanthemums can survive winter in the ground if they’re hardy varieties (like ‘Hardy Bonanza’ or ‘Dwarf Spray’). For colder zones (Zones 5-6), digging and storing them indoors or in a garage is safer. Always mulch heavily (6+ inches) if leaving them outside to protect roots.

What do I do if my chrysanthemums get frostbite or look mushy during storage?

Frostbite (brown, crispy leaves) is usually harmless—just trim the damaged parts in spring. Mushy stems or rot? That’s a sign of overwatering or poor airflow. If storing indoors, reduce watering to once every 2-3 weeks and ensure pots have drainage holes. For outdoor mulched plants, check for soggy soil—drain excess water if needed.

How do I know if my chrysanthemums will survive the winter?

Look for green, firm stems and roots when you dig them up (or peek under mulch). If they’re shriveled, black, or smelly, they’ve likely died—start fresh with new plants next year. Healthy overwintered mums will sprout new growth by late winter or early spring. Patience pays off!