It’s not unusual to feel disheartened when you had high hopes for a gorgeous colorful plant in bloom that quickly fades and withers away to nothing.
If that’s happened to you with a fall chrysanthemum (aka mums plant), you won’t be the first to wonder how to keep mums alive.
There is a knack to it but it only works on hardy types. Some are forced to bloom and destined for the compost pile.
Be Smarter than the Sellers
In the fall, the garden centers are full of potted mums ready for you to pick up, take home, and enjoy colorful blooms without any effort. That’s because the blooms are forced.
Forced blooms will not last. They’re a sign of a plant that’s nearly done. They’re terrific for sales stats in garden centers, but they’re short-lived once you get the plant home.
The best mums to buy later in the season are the ones that are yet to flower. That’s right, look for the plants with unopened buds. You want the plant to bloom in your home or garden. Not in the store.
Deep Containers Indicate Bigger Roots (Hardy Varieties)
For those with the seasonal shopping habit of buying mums every fall, chances are you’re buying the wrong type.
Hardy chrysanthemums can be overwintered indoors, potted up, or even grown in hanging baskets. The florists or cutting variety of mums are the shallow-rooted ones, bloom once, then get tossed in the compost pile.
Naturally, if the plant is labeled as being a hardy mum, it will mean it’s a perennial, capable of being overwintered indoors, and returning year after year either potted up or planted in the garden.
Annuals won’t return. You’ll spend the rest of the season nursing it despite it approaching its end of life.
The core difference between the two types of chrysanthemums is that hardy mums develop deep underground roots. Those are how it survives the winter.
Shallow-rooted indoor mums don’t have a strong enough rooting system to survive the slightest of frosts.
Start with Mums that Haven’t Bloomed
The entire playbook or tips and tricks to care for mums will do no good if it’s already far too gone by the time you get a chance to practice your green-thumbed skills.
Get a plant before it blooms!
Better yet, speak to florists or the staff at garden centers to find out when they’re expecting fresh flowers to be delivered. Buy them the day they arrive.
Supermarket plants are there for decoration only. It’s pot luck if something of survivable quality arrives. They rely on a super quick turnover.
If the plants aren’t bought up quickly, they wind up out the back in the trash. These won’t even be watered, let alone fertilized.
The result is they get fed, watered, slow-release fertilizers dropped into the soil, but the thing they never get is repotted.
The longer mums are potted up in containers that sit on the shelves at the stores, or in supermarkets, the bigger the root ball gets.
Root-bound plants struggle to grow, let alone bloom. That’s why, the first thing you should do when you get a chrysanthemum plant home is to repot it, and with a better potting mix.
Repotting Mums in Better Quality Potting Soil
This applies to both types of chrysanthemums. Garden varieties too because you never want to plant these outdoors late in the season. Keep them potted, indoors, and plant them outdoors in spring.
Something to understand about the blooming cycle of hardy mums is that hot temperatures encourage blooms, while cooler temperatures keep the blooms on the plants for longer, without the colors fading.
For that reason, you want your garden mums planted early in the season. Not just so they benefit from the hotter summer temperatures to get the blooms going. But, more so for the root development.
If you’re buying your plant later in the season, keep it potted, in good potting soil, and focus on strengthening the roots, not forcing it to bloom.
The first thing to do with any mums, regardless if you’re trying to keep it alive or force it to rebloom is to repot it. These become rootbound fast.
Sometimes, depending on how big the root system is, you may be able to divide it to pot up more than one plant.
Plant Hardy Mums Outdoors in the Spring, Not in Early Fall!
According to the National Chrysanthemum Society, the ideal soil acidity is a pH of 6.5, a mix that drains well, and is enriched with compost.
Fertilizer helps indoor plants, but if you’re planting a hardy mum in the garden, September is NOT when to plant in the ground soil. Keep the plant alive over the winter and then plant it in the garden in the spring to give it a full summer season for roots to grow strong.
If you plant a hardy mum near fall, the roots will more likely be killed by the first frost.
To give it the best chance of developing a strong root system, plant in spring and apply a standard garden fertilizer, but also give it a boost with a small amount of super phosphate.
Hardy mums can only survive cold temperatures when they have a strong rooting system. Super phosphate speeds the process along helping them survive the frost.
The trick to keeping mums alive is to focus on root care. Worry about handling blooming later. Keeping it alive by encouraging strong root growth is how to set these plants up to survive multiple winters.
How, When, and Where to Plant Mums in the Garden
Early spring, after the last frost date is when to get digging. You want your garden soil to have good drainage. If your soil is more clay and rocks, you’ll need to amend the soil. Use a garden soil potting mix.
Where to plant hardy mums are in the sunniest spot of your garden. Keep in mind that the more sun they get, the more watering they’ll need.
When transferring to ground soil, dig the hole an inch deeper than the pot it’s used to growing in and at a width that’s double the diameter of the root ball.
Too much bigger can trigger transplant shock, which never ends well, but you still need to go that little bit bigger because you want the roots to take hold underground.
To make sure it does, when you gently take the plant from its pot, use your thumb and forefingers to fluff the soil and separate some of the roots. The more space there is between the roots, the better air circulation there will be once it’s in the ground.
If you’re planting more than one or adding to an existing flower bed, it needs a couple of feet of spacing for when it fills out.
Finish Off with a Layer of Mulch
Good mulch materials for adding around mums are straw, grass clippings, shredded leaves, and shredded bark. Particularly, the bark because that not only helps with moisture retention but also for insulation later in the season.
Around 2 inches of mulch mounded around the base of the plant is sufficient for insulation and moisture retention.
Do Not Prune Off Cold Damaged Foliage
Once in the garden, hardy mums stand the best chance of survival when they have the most insulation. Dead foliage is still shelter. It staves off some hard-hitting cold winds and shelters the soil from rain saturation.
Anticipate it but don’t try to fix it. Let the damaged parts shelter the plant. It is still providing some insulation.
Cut mums back in the spring after the last expected frost date to prepare it for its next flowering season. Most garden mums last for four years. With proper care, that can be extended, but the colors typically aren’t as vibrant on mature plants.
Let the Sun Shine the Light
Mums need little light, but they still need some. At the very least, three hours of direct sunlight keeps them alive. Six hours of exposure to sunlight is when they flourish.
Forget using grow lights for chrysanthemums. They can be effective for greenhouse growers forcing florist varieties to bloom. That’s the throwaway type you find lining shelves at supermarkets.
Mums and grow lights are for inflating sales stats at nurseries. They don’t do you any good unless you plan to buy a plant to throw away.
Don’t Mistake Light for Heat
Mums are short-day flowering plants favoring the cooler temperatures. You’ll start to see the potted varieties go on sale in late summer. They are a transition plant that extends the flowering season.
But, when summer temperatures are still soaring in the high 90s, the colors fade fast. You’ll spend more time deadheading spent flowers than you will be enjoying the colorful blooms.
In the warmer days, have your potted plants indoors and set them out in the cooler evenings. They’re terrific for brightening up doorsteps, patios, and decking areas.
Later in the season when the day temperatures start to drop is when you can leave these outdoors more often.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.