When I first attempted to grow Mums, my plants kept dying before I could enjoy their jewel-toned blossoms. That’s when I decided to do some research to figure out what my plants were going through.
Your potted Mums are dying because they may be suffering from a fungal disease like Verticillium, Septoria leaf spot, or Botrytis. They might have been attacked by a parasite like Pythium. You might be underwatering or overwatering them. Or they lack nutrients for their growth.
I’ve written more details below on why your potted mums are having trouble growing and what you can do to help them recover.
Why Are My Potted Mums Dying?
If your potted Mums suddenly start dying out of nowhere despite good care, you might be dealing with fungal issues.
You see, Chrysanthemums bloom in the fall. Most will continue to thrive long after other summer flowers have stopped producing flowers. While those late blooms do a lot to beautify your garden, they also put the plant at risk.
The weather starts to change slowly once summer ends. Days become shorter, leaving less time for the sun to evaporate moisture in the soil. On top of all that, temperatures become cooler.
This cooler and wetter environment is perfect for mold and fungi spores to thrive. Fungi can attack the plant, causing disease and killing it from within.
Here are some of the most common fungal diseases that will kill your potted Mums.
Pythium is a plant parasite that acts very similarly to fungus. While most parasites will attack plants regardless of their condition, Pythium only does so when conditions are just right.
It’s naturally present in most soils. However, it only goes under attack when the plant is experiencing some type of stress. For Mums, it usually goes after waterlogged roots. It commonly kills Mums in the Fall because the soil is unable to efficiently evaporate.
Pythium causes issues. This includes stunted growth, discoloration, root rot, and eventual death.
Verticillium is a soil-dwelling fungus that’s difficult to bounce back from. When it attacks plants, they will begin to wilt quickly. The fungus turns the veins of the Chrysanthemum plant yellow, which prevents nutrients and water from flowing.
The problem with Verticillium is that fungicide does not affect it. Once it takes hold of the plant, there’s no way to stop it. To make matters worse, the fungus can spread to nearby plants and affect the soil quality.
The only way to truly address it is to remove the plant and burn it to control spread.
Septoria Leaf Spot
If the leaves of your Mums plant are looking a bit worse for wear, it could be dying from Septoria. This fungus affects a wide variety of plants. This even includes tomatoes.
The fungus spores hide in the soil and wait for ideal conditions to attack. Usually, it starts to flourish in damp conditions. It has a particularly nasty effect if water left to sit on the leaves of the Chrysanthemum.
The leaves are usually the first to show symptoms of the fungal disease. Not only will they wilt, but they may develop large spots of brown.
Also known as gray mold, Botrytis blight is a fungal disease that affects the flowers. The mold grows over the buds, quickly killing the flowers and weakening the plant.
The fungal spores favor warm days and cool nights, which is why Botrytis affects Chrysanthemums so much. Overcrowding and excess moisture will only exacerbate the issue and make the fungus kill the plant faster.
How Do You Revive Potted Mums?
The good news is that you can revive dying plants. If you catch the issue early on, you may be able to address the fungal problem and help your Mums flourish again.
Here are a few things you should do to restore your potted Mums.
The first thing you should do is apply an appropriate fungicide. Fungicides inhibit growth and can kill the spores on contact.
There are several products out there to try. Ultimately, the type of fungicide you use is going to depend on the issue you’re dealing with. That said, many gardeners have fungicides that contain chlorothalonil, mancozeb, myclobutanil, propiconazole, or thiophanate methyl.
Those chemicals can address some of the most common fungal diseases. Alternatively, you can try natural remedies if you don’t want to deal with chemical-based products.
Either way, it’s best to apply fungicides early on to prevent spores from taking hold in the first place. If the plant is already affected, treatment may help to prevent further spread.
Ensure the Plant Has Proper Drainage
Take a look at the pot you’re using. Does it have proper drainage holes?
Chrysanthemums need adequate drainage to prevent issues like root rot and fungus growth. Move the plant to a large pot that can efficiently get rid of excess water.
Prune Dead or Diseased Growth
To promote new growth, you need to get rid of the old stuff. Pruning is essential in the recovery phase. It gives the plant a chance to direct energy toward producing new stems and leaves.
Using pruning scissors, cut back any dead or diseased leaves. You should also remove dead flower buds or any extreme discoloration.
Pruning may leave your plant looking a bit bare for the time being. But, it makes room for healthy growth.
Keep the Soil Damp
Ideally, your Mums should be getting about an inch of water per week. As mentioned earlier, too much water is dangerous for these plants.
So, you need to check the soil frequently and monitor conditions. You don’t want to let the soil dry out completely. It should remain damp at all times. But, you have to avoid letting water sit.
As a general guide, lightly water the plant every two days.
Provide Plenty of Sunshine
Chrysanthemums are sun-loving flowers! They require at least six hours of direct sunlight every day to reach their full potential.
Place your potted Mums in a sunny spot. Once you’ve pruned dead growth, the sunlight will trigger some new growth.
Fertilizer can give your Mums a nice boost of nutrients. These plants require a good amount of potassium and nitrogen. They will take advantage of the fertilizer most during the vegetative phase.
This is when the roots, stems, and leaves are developing. Because you’re trying to revive a dying plant, the fertilizer can benefit you here, too.
Side dress a standard 5-10-10 fertilizer. Do this only once. Like water, too much fertilizer can harm the plant.
How Long Do Potted Mums Last?
You might be wondering if Mums are even worth trying to salvage. Many gardeners treat Chrysanthemum plants as annuals. But, they’re technically perennials.
Whether the plant is in a garden bed or in a pot, it needs to survive over the winter to come back the next year. This can only happen if the plant has the opportunity to grow strong roots.
Generally, Chrysanthemums planted early in the spring have no problem overwintering. By the time the temperature drops, the root system is robust enough to support the plant during harsh temperatures.
However, those planted in the summer for a late Fall bloom usually don’t make it through the winter.
With good care, a potted Mum can live for three to four years.
How Long Do Blooms Last?
Chrysanthemum plants are capable of blooming continuously for up to six weeks in the Fall. This is just a general range, as different cultivars might bloom for a shorter period.
The temperature can also affect how long the flowers bloom. If daytime temperatures are still pretty high, the plant may only bloom for about three weeks.
Why Are My Potted Mums Turning Brown?
Before Potted Mums die off, they may turn brown and discolored. Take this as a sign to take action!
Browning Mums are salvageable, but you have to act fast. Beyond the aforementioned fungal diseases, there are a few different reasons why your Mums could be turning brown.
If the leaves of your plant are turning yellow and frail, a lack of proper drainage is likely to blame. Sitting water is a huge problem for Mums.
They must grow in a nice sandy loam soil to see the best results. Your pot should also have several holes to ensure that the roots aren’t waterlogged.
Aphid infestations are very common for Chrysanthemums. The sap-sucking insects are tiny. However, they will overtake a plant in droves!
When they do, aphids typically feed off sap in the leaves. This causes the plant to turn yellow or brown.
You can easily treat aphid infestations with natural or chemical-based insecticides.
For the most part, Chrysanthemum plants are hardy enough to deal with tough weather. But, major storms can turn the plant into a brown mushy mess.
Heavy rains, hailstorms, or even early frosts can have a big impact on the plant. It will turn the leaves and stems brown. In severe cases, the tissue within the plant can become soft and impossible to salvage.
The Natural Flowering Process
Finally, your Mums can be turning brown due to the natural flowering process. This reason is innocent enough and doesn’t require any intervention from you. It’s just part of the plant’s life cycle.
After the blooming phase, the buds can dry out and turn brown. As the temperature drops, the entire plant will turn brown as well.
Should You Deadhead Mums?
If you want your potted Mums to last as long as possible, deadheading is a must. This process involves removing spent flowers once the blooms start wilting.
To deadhead the plant, simply use pruning scissors to cut a diagonal line on the stem. You should cut the stem just above the set of leaves closest to the bloom.
It’s best to remove spent flowers when they look dead and dried out.
There are a few benefits of deadheading Mums. The biggest is that it encourages more flowers to bloom. Leaving the flowers on the plant will force them to mature and go to seed.
By deadheading them, you’re stopping the plant from multiplying. As a result, it will grow more flowers. It’s a great way to prolong the life of the plant and extend the blossoming phase a bit.
You can also use this practice to divert energy as needed. Earlier, we talked about reviving potted Mums that were dying. In those instances, deadheading forces the plant to use its energy to grow proper roots and vegetation.
When there are no flower buds to bloom, the plant will use its energy elsewhere.