8 Reasons Why Your Potted Mums Are Dying

Potted mums are a fun way to brighten up your home during the spring and fall. They come in a variety of hues, so you are sure to find one you like. But nothing lasts forever, and eventually, your potted mums will start to wither away and die.

Here are eight reasons why your potted mums are dying:

  1. Diseases
  2. Underwatering your potted mum
  3. Overwatering/poor soil drainage
  4. Low temperatures/extreme weather conditions
  5. Pest infestations
  6. Inadequate sunshine
  7. Negligence
  8. Old age

This article will dive deeper into how these eight reasons impact your mums’ health. I will also offer tips on how to combat some of these issues and possibly prolong the life of your mum!

1. Diseases

Potted mums are susceptible to a variety of diseases. Each one can cause your mum to become sick and eventually die if not properly treated. 

Here are four of the most common diseases that potted mums are susceptible to and the ways you can treat them:

Botrytis Blight

Botrytis blight, also known as gray mold, is caused by Botrytis cinerea. This fungus attacks the most vulnerable parts of the plant when high humidity is present or after an extended period of rain in the Spring and Summer. 

Botrytis blight attacks almost all garden perennials, ornamental trees, and shrubs because it thrives on overcrowded plants.

If you notice your potted mums becoming discolored or wilting, this is a sign of Botrytis blight. 

You’ll also know you’re dealing with Botrytis blight if your buds fail to open or your flowers appear old. 

Treating Botrytis Blight

Being a fungal disease, your best weapon against Botrytis blight is good sanitization. Disinfect your gardening tools with a household bleach solution before and after using them to prevent the fungus from spreading.

Pruning the diseased plant by cutting off any infected buds, flowers, leaves, etc., is an excellent way to stop Botrytis blight from spreading. Also, pick up any fallen debris you may find in the pot or on the ground and destroy them immediately. 

If possible, burn the infected plant material, do not throw it out! 

Preventing your plant from becoming stressed helps keep Botrytis blight at bay, exactly why you should ensure it receives an adequate amount of water and sunlight. Pruning can also be a preventative measure as it allows for improved air circulation.

However, if you have noticed that the Botrytis blight has spread past your potted mums and onto other plants, then a fungicide is needed. Choose a fungicide that specifically treats Botrytis blight like the Ortho Max Garden Disease Concentrate (available on amazon.com), which is known to effectively control ornamental plant diseases. 


Pythium is a species of plant parasite that has similar characteristics to fungus. What makes Pythium closer to a fungus is the fact that it attacks plants when the conditions are right, while most other parasites attack a plant no matter its condition. So if your potted mum is currently experiencing stress or has been recently overwatered, Pythium is likely to attack.

Some of the signs that Pythium is attacking your mum are stunted plant growth, the roots develop a brown tissue (rot) that causes the plant to weaken and die, and lastly, the plant starts to yellow and wilt, two sure signs you have a dying mum on your hands. 

Treating Pythium

Pythium has the ability to wipe out substantial flower beds, causing significant damage and plant loss. So the best way to control Pythium is to prevent the disease from occurring in the first place. 

Pretreatment of soil using a heat-pasteurized potting mix that is safely stored and unable to be contaminated by other soils is an excellent way to prevent Pythium. Using pretreated water irrigated for a pond or stream is another way to prevent Pythium from occurring.

Sanitization is another way to keep Pythium at bay. By disinfecting every tool and surface that comes in contact with your potting soil, you significantly cut down the risk of your plant contracting the disease.  

If Pythium does start to impact your plants, applying a fungicide will help treat the issue. If you are repotting your potted mum, treat the soil before, during, or immediately after the repotting for optimal results.

Septoria Leaf Spot

As the name suggests, Septoria Leaf Spot is a fungal disease that attacks the leaves of your plants. Your plant’s leaves are the first to show the symptoms of Septoria Leaf Spot. The leaves will wilt and develop brown spots. So if you have noticed the leaves of your potted mums looking ragged, this fungal disease could be the culprit.

Septoria Leaf Spot flourishes in damp conditions. So if you overwater your mum or leave the water to sit on its leaves, you are providing the perfect breeding ground for Septoria Leaf Spot to grow. 

Treating Septoria Leaf Spot

Since this is a fungal disease that goes after the leaves, proper leaf care is necessary to prevent it. In the early stages of Septoria Leaf Spot, removing the affected leaves can be enough to prevent the disease from spreading further. 

You will want to destroy the leaves by burning or some other method to prevent the disease from possibly spreading to other plants.

When watering your potted mum, do not water from an overhead position. Overhead watering makes your plant a magnet for different infections and can spread disease from plant to plant. 

As such, you should water the plant at its base to keep the flowers dry. Watering at the bottom of the plant will repel infections and disease from seeking a home on your potted mum!

Pruning is another effective method for preventing Septoria Leaf Spot. By pruning your plant, you allow for better air circulation, which gives your plant more room to breathe and dry after watering. Faster drying equals less chance of becoming infected.

Finally, you can use a fungicidal spray to treat Septoria Leaf Spot if all else fails. Fungicides cannot cure already infected leaves; they will still die off and need immediate removal. But fungicides can protect uninfected and new leaves from meeting the same fate.

Verticillium Wilt

Verticillium wilt is a fungal disease that dwells in the soil. This disease invades vulnerable plants through their roots, spreading through the plants’ vascular system. Plants begin to wilt and curl quickly and turn yellow before eventually turning brown and dying.

Verticillium wilt affects all varieties of plants, from garden annuals to fruit and vegetable crops. It can even affect trees, killing off their branches and stems. This fungal disease is ruthless in how quickly it spreads and kills plants.

Because Verticillium wilt mimics the symptoms of other environmental issues and plant diseases, it is difficult to accurately diagnose if it is the cause of your plants’ decay.

Treating Verticillium Wilt

If your potted mum has Verticillium wilt, we are sorry to say there is nothing you can do for it. Verticillium wilt is a vicious fungal disease that no fungicide can treat, and once it takes its hold of a plant, there is no way to stop it from killing the plant and moving onto other plants nearby.

The most effective method for treating Verticillium wilt is to build up your plants’ resistance to it. A regular watering schedule and fertilizing on schedule with a low-nitrogen, high-phosphorus fertilizer can help keep Verticillium wilt away from your potted mum.

Pruning away dead and dying branches is also an excellent preventative measure. And if you have a way to have your soil solarized (where it can be heated to high temperatures that kill off fungal diseases), you are setting yourself up for plant care success!

2. Underwatering Your Potted Mum

All plants require a certain amount of water to keep them thriving and living their healthiest life. If you underwater your plant, you are setting yourself up for plant failure. The risk of underwatering your plant is why regular watering schedules are necessary for plant care. 

Potted mums should be watered frequently when they are first potted, but once they are more established, their watering schedule can go to once a week. Give your established potted mum an inch of water once a week, and you should see it living its best plant life.

Be sure to water the mum close to its roots. As we learned above, overhead watering is a leading cause of fungus growing on your plant! If you notice your potted mum is looking a little sad, you can place the pot in a bucket of water that has two to three inches of water in it. Let your mum absorb the water, and you should be good to go.

3. Overwatering/Poor Soil Drainage

As much of an issue as underwatering your potted mum is, overwatering it is also a huge problem. 

Overwatering your potted mum can lead to waterlogging problems, and a waterlogged plant is more susceptible to root rot and other fungal issues. That is why having your mum in potting soil that has good drainage properties is essential.

Potted mums do best in soilless mixtures. These soilless mixtures should be one part coarse builder’s sand, one part peat moss, and one part perlite. This soilless mixture allows for good water drainage, keeping your mum moist, and avoiding the risk of waterlogging/overwatering.

4. Low Temperatures/Extreme Weather Conditions

All plants have temperature and weather conditions that help keep them blooming and in good health conditions. 

Your potted mum’s breed will determine the ideal temperatures. Some mum breeds can tolerate down to zero degrees, while others can tolerate between sixty to seventy degrees. So knowing your mum’s breed will help you understand the best temperature conditions to keep it happy.

For potted mums, the ideal weather conditions are sunny days with decent airflow. If you keep your potted mums outside, bring them inside during heavy rainstorms with strong winds to protect them from being waterlogged or possibly knocked over and destroyed.

5. Pest Infestations

Aphids, earwigs, mites, slugs, snails, and thrips are all waiting to turn your potted mum into their own personal, all you can buffet. These pests bring along hearty appetites and problems that can damage and even kill your mum.

If you suspect your potted mum is under attack from these pesky invaders, grab a white styrofoam cup or piece of paper, place it under the mums’ leaves, and shake the plant. If you see black or red dots after the shake, you have an infestation on your hands.

However, some of these pests are not so easy to find. Aphids are the same green as your plants’ leaves, so you will have to get up close to your plants’ leaves and inspect them. If you do not want to get that close, you can always take a damp cloth, wipe your leaf’s underside, and see what comes off the plant.

A sure sign of an infestation is if you notice small holes in your plant that are brown and yellow. These are the spots where aphids steal the plant’s water and nutrients, leaving it to become sickly.

If you want to learn more about dealing with aphids on your houseplants, you can read my other here: How to Control Aphids on Indoor Plants (15 Tips)

Treating the Infestation

To treat your pest invasion, spraying insecticide or washing your plant with a bar of insecticidal soap will do the trick. Insecticides come in all-natural options, so if you are opposed to chemical pesticides, there are still options for you to use.

Another more natural option is dunking your potted mum into a bucket of room-temperature soapy water. Immersing your mum will get rid of the aphids without doing any damage. Rinse the plant with clean water and allow it time to dry in a well-ventilated area, like outside or in your plant room if you have one.

6. Inadequate Sunshine

When plants receive inadequate sunshine, it hurts their health and appearance. And since  mums love the sun, it’s best to place them in a spot with adequate sunlight. 

Placing your potted mum in a sunny window that gives them bright, indirect light will keep them happy and blooming. If you place your potted mum in a window where it will receive direct sunlight, move the plant after around four hours to prevent the leaves and blooms from becoming scorched. 

If you choose to place your potted mum outside, keep them outside for about five hours, preferably between the rise of the morning sun and when the afternoon starts to get shady. Too much direct sunlight can cause the plant to become scorched. 

A word of warning: If you keep your potted mum indoors, do not give it light from an artificial source like a plant light. Artificial light interferes with its bloom cycle, and you want to avoid that happening.

7. Negligence

I am sure if you asked anyone who has ever owned a houseplant what the number one reason why they had a houseplant die is, they would say negligence.

It is easy to neglect our houseplants. After all, they are not like children or pets who make noises to let us know when they need food or water. Houseplants sit wherever we place them, and that is it.

So to avoid killing your potted mums due to neglect, here are a few suggestions to keep in mind:

  • Place them in a visible spot. If you have a favorite reading spot by the window or a big windowsill that looks out across a lake or your yard, these are good spots to put the potted mum. By placing it somewhere you often are, you have a much better chance of remembering to care for it.
  • Download a plant app. There are numerous plant apps that you can download on your phone to alert you when a specific plant needs water. Most of them are free to use, so why not give one a try?
  • Add it to your daily routine. If you have a daily routine, add watering your plants into that routine. Maybe while you wait for your coffee to brew or your toast to finish toasting, you can spend a few minutes watering your plants. It will be a quick win in your day, as it will give you a few moments of relaxing and intentional living before starting your possibly chaotic day.

8. Old Age

If your potted mum manages to avoid all of the above issues, then it can have a lifespan of three to four years.

But nothing lives forever. So if you have had your potted mum for a long-time and you have found none of the above issues wrong with it, it could simply be old age that is killing it.

Old age is the most natural death your plant can face, and sadly there is nothing you can do to prevent this from happening. 

However, you can prolong your mum’s life by watering it regularly and ensuring it gets enough indirect sunlight for its needs. Monitoring your potted mums will boost your chances of spotting any issues or infestations early enough and make the necessary adjustments. 

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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