How To Grow And Care For Garden Chrysanthemums (Mums)

Keep your yard dazzling with vivid reds, golds, and yellows with the addition of mums.

Fact checked by Elizabeth BerryFact checked by Elizabeth Berry

Perhaps no other fall flower creates as much excitement as chrysanthemums—or mums as we like to call them. From high school homecomings to gardens bursting with color, we Southerners can’t get enough of them. 

The autumn arrival of these brightly colored blossoms signals the coming of shorter days, cooler weather, outdoor decorating, cozy sweaters, pumpkins, apples, and so many more wonderful things. If you are looking to make Thanksgiving even more special, a centerpiece featuring mums will set the celebratory tone.

There are two main types of mums: florist and garden. Florist mums are annuals, enjoyed for a season and then gone. Garden mums, however, are perennial, able for us to enjoy year after year. 

These happy blooms are best planted in the spring once the ground is free of frost. This gives them time over the hotter months to establish roots before they become showstoppers in the fall. If you plant garden mums in the fall in colder climates, odds are they will not survive the winter. Follow these easy steps to get the best out of your mums this fall.

Please bear in mind that the Chrysanthemum is toxic to dogs, cats and horses. As long as your fur family does not have access to the plant, feel free to enjoy the fun explosions of color that come with a garden featuring mums.

Plant Attributes

Chrysanthemum Care

While care for perennial mums in your garden requires maintenance throughout the year, it's not too difficult. They need plenty of sun each day and regular watering in well-draining soil. Fertilizing weekly can help encourage blooms, and these flowers are hardy across the South.

Light

Whether you place your mums in pots to decorate your porch or use them as a bedding plant, you want to choose a spot that gets a minimum of six hours of direct sunlight daily—even more for bigger plants. If mums don't get enough sun, they can become leggy and not grow enough buds.

Water

Mums have shallow root systems, which can dry out quickly. Water mums when the top 2 or 3 inches of soil have dried out, as long as the plant continues blooming. Keep mums in moist soil, but not wet—drainage is important to keep fungi from growing. If you're growing mums in containers, water every other day.

Soil

Mums prefer well-draining sandy or loamy soil. Because they need so much water, you can add mulch, especially in the winter, to help retain moisture and insulate the roots.

Temperature And Humidity

Chrysanthemums are tolerant to the U.S. Department of Agriculture's hardiness zones 5 to 9, with some varieties able to tolerate lower temperatures.

The optimal temperature for garden mums outdoors is between 62° and 72°. Mums thrive in humid conditions, which should be between 70% and 90%. This makes the South prime territory for this gorgeous plant. The humidity level will affect their mass and growth. However, too much humidity can be a breeding ground for fungi. Encourage air circulation by spacing plants at least 1 foot apart.

Fertilizer

Mulching in the winter keeps the soil from going through a cycle of warming to freezing and back to warming, which only confuses the plant as to whether it should stay dormant or begin new growth. Once the plant starts to grow in the spring and summer, you should apply a water-soluble organic fertilizer once a week. In the spring, opt for a nitrogen-rich fertilizer to help encourage foliage; once buds appear, switch to a phosphorus-rich fertilizer. Fertilize through the summer.

Types Of Mums

While the Chrysanthemum genus includes about 40 species, there are countless horticultural varieties and cultivars of mums available. Here are a few:

• ‘Yellow Sarah’: This perennial garden mum is bright yellow and blooms late in the season.

• 'Rose Seranade': This early season mum is known for its reddish-purple flowers. It blooms in August and September.

• 'Mabel White': Also called 'Belgian White', this garden mum is known for its white flowers and September and October blooms.
  

Related: How To Plant Bulbs in Containers

Pruning Mums

Once your mum has been planted in the ground, cut the stems of the mums at 3 to 4 inches above the ground. Leaving a little bit of the stems will ensure you have a full plant next year, as the new stems will grow from these trimmed stems.

Do not prune your mums in the winter. In the spring and summer, when your mums are about 6 inches tall, pinch of 3/4 an inch from each branch. Do this again when the plant is 1 foot tall. This will encourage a bushier mum with lots of blooms. Stop pinching off branches 100 days before your mum is set to bloom.

Propagating Mums

There are several ways to propagate mums, from cutting and dividing. It's good to divide the mum every couple of years as it can encourage new growth from the plant.

From A Cutting

1. Using clean shears, cut your mum's stems 4 inches from the top at a 45-degree angle, plucking leaves off an inch from the bottom.

2. Dip your cuttings in a root hormone and plant in a perlite and compost mixture.

3. It will take a couple of weeks for roots to grow, and then you can transplant them into larger pots or into your garden.

Dividing

1. Remove the mum from the container or dig it up.

2. Cut the plant and roots into sections with a sharp knife. Make sure each section has roots.

3. Replant them into containers or in your garden. 
   

How To Grow Mums From Seed

Growing mums from seeds requires trays of good quality and well-drained, fine potting mix. Get started about six to 10 weeks before the last frost is expected. This usually lands in a timeframe between February and March. Keep the soil humid but not wet and at about 70° to 75° to see the seedlings appear in 10 to 21 days.

Potting And Repotting Mums

Mums are ideal for container planting because of their shallow root systems. Although considered a perennial, you can use those pots of blooming mums sold in the fall as annuals to replace summer annuals that are past their prime. Tuck the mums in beds, borders or planters to keep the color coming until frost.

Mums purchased from large garden centers are likely to be root-bound and starving for soil, water, and nutrients. You'll need to repot them and give them plenty of room to breathe. Pick a container or garden spot that offers the mums ample space for the root ball to spread out and grow. Use a loamy potting mix, and add some mulch or fertilizer to the soil.

If you planted garden mums for your fall lawn, you can pot them to help them survive the winter and replant them in the dirt once spring comes.

Related: When To Move Mums Out To Ensure They Last All Season

Overwintering

Often, it isn't necessarily the cold weather that kills mums, but the ice that forms around the roots if the mums are sitting in water. Soil that drains properly is key to successfully overwintering mums. You may also want to choose a somewhat sheltered location from strong, cold winter winds, which can also be harsh on mums. Once the ground has frozen, add a layer of either mulch, straw, or leaves over the plant to help keep it insulated.

Common Pests & Plant Diseases

Mums are susceptible to several fungal diseases, like powdery mildew and rust. Caused by fungi, powdery mildew looks like white or gray flour dusted on plant leaves. It can stunt the plant’s growth, cause leaves to drop, and decrease flower yields. It spreads when there’s lots of humidity, so the best way to prevent is to prune to ensure there’s enough air circulation between stems. Treat by pruning infected areas with clean shears and treat with a fungicide, like neem oil or sulfur.

Rust, powdery orange spots on the underside of leaves, is also caused by a fungus. A bad enough infection can weaken the plant and limit blooms. Prune infected leaves, plant the mums further apart for better air circulation, water the soil while avoiding the plant, and treat with a fungicide.

Like many other flowers, mums are susceptible to aphids, which feed on sap in the plant’s tissue, distort growth, and can kill the plant. While all kinds of aphids will feed on mums, these flowers have their own chrysanthemum aphid (Macrosiphoniella sanborni). Regularly inspect your mum for aphids. To get rid of them, blast the plant with water every few days or treat the mum with insecticidal soap. 

Spider mites are another common pest. These tiny mites are more prevalent during hotter temperatures and suck the sap out of the plant. Small yellow spots and a dusty appearance on leaves signify a light infestation, while a bad infestation will have dropped foliage, withered flowers, and silk webbing. Treat with neem oil and insecticides and consider throwing out badly impacted plants. 

How To Get Mums To Bloom

To maximize the chrysanthemum's bloom time, buy the mums just as they are starting to break bud. This strategy means buying mums with the least number of buds showing color since you will see a better bloom from this plant later. You'll want to ensure enough buds are showing to check the color of the plant you're buying. Not only will you be sure of what color mums you'll end up with when they fully bloom, but the flowers will also last longer this way. Once the buds open up more, you are practically guaranteed flowers.

As your mum grows and flowers, you should deadhead, or remove spent and faded blooms. This will force the plant to spend its energy on growing roots rather than new blooms, which will help ensure you will have beautiful, colorful mums throughout the next year. Pinch off buds every two to four weeks to ensure you have sturdy plants come fall.

Common Problems With Mums

Mums are relatively easy to care for. The challenges that present with mums largely have to do with water and light issues. If you place them in all-day sun and keep the soil moist, not oversaturated, they should thrive. Here some issues you may encounter and how to handle them.

Leggy Stems

If the stems are lanky and floppy, this can be caused by too much shade. Cut them back and move your mum to a brighter spot where it will receive six hours or more of sun each day.

Woody Stems

Stems can sometimes become too woody, and this is due to poor watering. Water when the top few inches of soil are dry or the leaves are wilted.

Leaves Turning Yellow

The discoloring of leaves could be a result of too much watering. If the soil is soggy, let the plant dry out and move it to a spot with well-draining soil and a little less sun, if needed, so it will require less water. Lack of nutrients, poor fertilization, and a fungal infection can also cause this symptom. Do a soil test to determine what nutrients the soil is lacking if necessary. Water the plant at its base, and don't wet the leaves to avoid fungal infections.

Frequently Asked Questions

How long can mums live?

With ample time to grow their roots, garden mums can live for three to four years in USDA Zones 5 to 9.

What plants are similar to mums?

If you'd like to try give another fall flowering plant a go, check out asters, a fresh alternative to mums.

Where should I place mums if growing them indoors?

Mums need six hours of sunlight a day, but too much sun will shorten their blooming cycle. Put your indoor plants in a place where they will experience partial shade. Protecting potted mums from heat stress will keep them blooming longer.

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