How to Repot Chrysanthemums in 9 Easy Steps

Whether you grow gardens, florists, or hardy mums in containers, you’ll want their roots to keep spreading and thriving so they can flower proliferously. Chrysanthemums sprout shallow roots with fine feeders and don’t tend to get woody in containers. They do, however, search for new spaces and can get rootbound in their container.

Chrysanthemums dislike being rootbound more than other species—they’ll bloom less, sport weak growth, and be subject to pests and diseases. You’ll also have to water them more often since they have little soil to absorb excess moisture. 

Repotting is simple. Once you know how and have the right materials, you can complete it in less than 10 minutes! There’s no rush for your first time, though, and I implore you to take all the time you need. Look closely at the roots, stems, and leaves during the process to see how plants react to transplanting. If your mum is rootbound, you’ll see it grow healthier, quicker, and bigger in its new container.

See for yourself how easy it is to repot your chrysanthemums! Follow these nine straightforward steps to move your struggling mums into their new homes.

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Step 1: Start During the Right Season

Chrysanthemums are frost-tender, and although they’re hardy, they can suffer damage during winter storms. Transplanting shocks plants since they rarely have to uproot themselves and find new locations in the wild. Don’t worry because they recover quickly from this shock during their season of growth. They put down new roots and stem shoots when they’re happy.

The best time to repot chrysanthemums is from midwinter through early spring. It varies depending on your growing zone. If you have frost-free, mild winters, transplant your mums starting in midwinter. If you experience extreme winter freezes, wait until a week or two before your last average frost date to start transplanting.

Some growers choose to repot during the fall, although this may threaten your mums’ survival chances if freezes are common. Only repot before the fall if you live in a warm winter zone or you are keeping your mums indoors in bright light until spring warmth arrives.

Step 2: Prepare A Larger Container

So it’s midwinter or early spring, and you’re ready to repot. First, find a container that is larger than the one your mum is in now. Chrysanthemums typically have short, shallow root systems, but mature specimens can get rootbound in their pot. Look for one at least two inches deeper and wider than the current container. 

Florists and garden mums are marginally frost-hardy from USDA hardiness zones 4 through 9. They’re even less hardy in containers outdoors since they’re aboveground and more subject to extreme temperatures. Use a thick, frost-proof container made of ceramic or stone. It’ll help keep your chrysanthemum’s roots warm and secure. 

Plastic containers work well during the growing season but are flimsy and thin. They offer little protection from cold temperatures, and mums in plastic pots are more susceptible to frost damage. Only use them long-term for hardy species that tolerate a cold climate and choose for tender species in warm zones.

Step 3: Create A Soil Mix

Chrysanthemums of all species appreciate rich, moist soil full of humus. They like adequate drainage and fare well with most soil mixes for containers. If you’re making your mix, use soilless materials with compost, like coco coir or sustainably sourced peat. Add some perlite or vermiculite for drainage, and mix it up well.

Compost is beneficial to add because it injects microbes, nutrients, and drainage capabilities into existing soils. A little in your mums’ soil will go a long way in helping them produce dozens of blooms in the autumn.

You’ll also want to add some fertilizer to the soil, as your plants appreciate the extra nutrients in early spring. Blend an organic powder fertilizer into the soil, or apply a liquid type a few weeks after repotting. If it’s still frosty in your ecoregion, consider holding off on fertilizer until temperatures warm and mums sprout anew. 

Step 4: Transplant Your Chrysanthemums

With ready soil and a larger container, you’re ready to get transplanting! Start by pruning long shoots on your mum. Transplanting damages roots, and removing some top-growth evens out how much energy the mum needs to keep stems alive while also adapting to a new pot.

After pruning, remove your chrysanthemum from its container. Tease the roots with your fingers, especially if they’re rootbound. You’ll want them to loosen and dangle down so they easily anchor onto fresh soil.

Layer some potting soil on the bottom of your new container so the mum sits at the right height. You don’t want roots exposing themselves or the plant to be low and have soil covering its base. Add more soil below where the shrub lies, or take some out to keep the mum’s trunk level with the pot’s top.

Step 5: Fill The Hole

Once your mum is level in its pot, it’s ready for more soil. Add the mix until it reaches the top of the mum’s base, pat it lightly, then water well. You’ll notice the soil sinks around the edges and isn’t at the level it needs to be anymore. Add more soil on top, then water again. Repeat until the soil doesn’t sink, and it’s at the perfect height in its container.

If your container has a drainage basin or water catcher, you might have to empty it a few times during this process. Chrysanthemums like moist soil, but they don’t like standing water on their roots. Put the drainage basin back once you finish filling the container with soil.

Step 6: Add Mulch or Compost

Compost or a similar organic mulch benefits most plants—it provides multiple uses like nutrients, soil life, and porosity. Add it on top after repotting your chrysanthemums, and they’ll appreciate the benefits. Porosity helps by keeping roots dry amidst rainstorms, yet retains moisture during droughts. It also creates air pockets that help mums’ roots breathe.

Compost is the ultimate mulch, although a few other amendments work similarly. Try leaf mold, dead leaves, straw, or grass and plant clippings for a similar effect. They’ll decompose on the dirt and add new life while protecting existing soils from the elements.

Chrysanthemums love humus, and compost is full of it. In the absence of compost or mulch, find humus or organic mulch products at your local nursery or online. They may seem like a last-minute addition, but they can make or break your mums’ survival chances during extreme weather.

Step 7: Water Often

After a successful repot, water your mums as often as they need. They’re a thirsty species and may need water once daily in hot weather or every other day under cool temperatures. They’ll especially need a moist environment while they put down new roots.

The finger test is an easy way to check if your mums need water. Simply stick your finger in the pot as deep as it’ll go and see if you sense moisture. If the pot’s wet up to the top, wait to water. If the top two inches are dry, water plenty until it flows freely from the container’s bottom. 

When rainfall and freezing temperatures occur, you can water less often. Otherwise, chrysanthemums love consistently moist soil so they flower, grow, and sprout roots readily.

Step 8: Monitor For Changes

When new growth occurs, you’ll know your repot is successful! Congratulate yourself, but still keep a close eye on your mums. Monitor them for aphids, powdery mildew, or wilting foliage. They’re more susceptible to pest and disease attacks while adapting to their new homes. 

Hose off pests as you see them, and treat diseases before they spread. Rust, petal spot, and leaf spot may infect susceptible mums in addition to powdery mildew. Most will grow okay without infections after repotting, but a watchful eye ensures that these issues won’t grow into larger ones if your mums do fight diseases or pests.

Aside from pests and diseases, it helps to watch for signs of water stress after repotting. Chrysanthemums like moist soil, but overly large containers can grow soggy if they receive too much water. Look for yellowing leaves that indicate overwatering and dry, crunchy ones that indicate too little water.

Step 9: Repeat Before It Gets Rootbound

Mums hate being rootbound! They’ll bloom less often, grow shorter, and produce fewer stems if subject to rooting stress. The best way to avoid this is to repot them before they grow rootbound or divide them into smaller containers.

Check mum roots by lifting the plant out of the pot a little after they establish themselves. If you see roots circling the edges of the soil, your mum is becoming rootbound. Your mum is happy in its current container if you don’t see any roots or the rootball won’t come out in one piece.

It should take two or three years before you’ll need to repot again. Younger plants grow quicker than older ones and may need a repot more often than that. Listen to your mums! They’ll tell you through their flowers, leaves, and new spring growth whether they’re thriving or need a new home.