3 Reasons For Dahlia Leaves Turning Brown[Fixing Guide]

Dahlias beautify the gardens with their beautiful and vibrant blooms. But without the green foliage, it loses its appeal.

If you notice your Dahlia leaves are turning brown then it is time to take some actions to save the plant. Otherwise, the plant can even die.

Now the question is – why are the Dahlia leaves turning brown?

Fungal problems, Pest attacks, and some Cultural management problems are the main reasons for it.

In this article, I’ll walk you through these problems and brief you about how to do their treatments. 

So let’s get down to it right away-

Causes and Solutions For Dahlia Leaves Turning  Brown

1.Fungal Problems Of Dahlia

Powdery mildew, Downy mildew, and Wilt are the three major fungal problems of Dahlia.

In the case of powdery mildew, the first thing you will see is a white powdery substance covering your Dahlia leaves. But as soon as the infestation becomes severe the leaves will turn brown

Downy mildew creates angular yellow spots on the leaves which soon turn the whole leaves brown. The leaves then become crispy around the edges. Then they eventually fall off. 

Fungal wilt is a very dangerous enemy of Dahlia. Plants can get infected with wilt at any stage. The leaves start to turn yellow and later brown.

Stem rot is another fungal issue of Dahlia. It usually occurs when the soil is heavy and poorly drained. It causes the leaves to turn brown and sometimes even black. 

Control Measure 

For any fungal attacks remove the infected leaves at once. Because the infected leaves can easily spread the disease to healthy ones. 

There are many kinds of fungicides available in the market. But it is important to check if the active ingredients in the fungicide are safe for application.

After removing the infected Dahlias spray a good and environmentally non-toxic fungicide by following the package instructions (Our pick: Spectracide Immunox Multi-Purpose Fungicide Spray).

There is no cure for wilt. So it’s best to remove the wilted plant as soon as possible. 

Some home remedies are excellent against fungal problems and you should definitely give them a try. Some effective recipes are mentioned here:

#Recipe 1:- Baking Soda Recipe


  • 4 teaspoons of baking soda
  • 2 teaspoons of liquid soap
  • 2 teaspoons of any cooking oil (olive oil, Vegetable oil, Soybean oil, etc.)
  • 4 liters of water


  • Mix all the ingredients and stir very well
  • Put it into the sprayer
  • Apply this solution to your infected Dahlia leaves

# Recipe 2:- Cinnamon Spray Recipe


  • 3 teaspoons of cinnamon powder
  • 500 ml of water
  • Few drops of liquid dish soap


  • Mix the cinnamon powder and water in a pot 
  • Let it stay overnight so that the cinnamon can get infused with water very well
  • Strain the solution with a fine cloth and pour it into the sprayer.
  •  Spray in the stem and leaves of the affected plant.

# Recipe 3:- Epsom Salt Spray Recipe


  •  1 tablespoon of Epsom salt  
  •   Half a gallon of water


  • Mix the salt and water 
  • Put into the sprayer
  • Spray this solution every week until the fungal problem solves

#Recipe 4:- Vinegar Spray Recipe


  • 3 teaspoons of apple cider vinegar 
  • 2 liters of water
  • Few drops of liquid soap 


  • Mix the ingredients very well 
  • Spray on the infected leaves twice a week until the problem is solved.

Note: In the case of all homemade recipes, always use a small part of the spray mix first to test in a small area of a leaf before starting to apply in the whole plant. 

Sometimes the leaves may burn then you can skip spraying the mixture. Or you can dilute the solution with water to make a milder mixture and try spraying again.

Preventive Measure

If you suspect any fungal problems then report the Dahlias in freshly prepared soil.

Do not water your Dahlia tubers after planting until new sprouting occurs. It can encourage stem rotting.

Add a mixture of sand, perlite (our pick: Organic Perlite by Perfect Plants), vermiculite, or peat moss with the soil to ensure good drainage. 

Avoid planting Dahlias in the soil where wilting has infected plants in previous seasons. Keep proper plant spacing to discourage fungal growth.

2. Pests Problems of Dahlia

Some pests like leafminers and leafhoppers can be the reasons why your Dahlia leaves are turning brown. 

Leafhoppers are serious pests of Dahlia. They are very tiny and green insects. They fly from one leaf to another and suck the leaf sap. The result of their feeding is brown and brittle leaves with stunted Dahlia plants. 

Leaf miner feeds on the leaves and the females lay eggs. As a result, The leaves dry out and turn brown. 

Control Measure

You need to choose the best and safe insecticide for your Dahlias that won’t hurt your beautiful flowers. (our pick: Southern Ag 10401 Natural Pyrethrin Concentrate)

Also, you can try Neem oil or insecticidal soap for organic control(our pick: Bonide Ready-to-Use Insect Soap). A good rinse with water will also help get rid of some pests to some point. You can put insect traps around to plants to catch them.

Here are some practical homemade recipes that you can make easily to control these pest problems:

#Recipe1:-Insecticidal Soap Recipe


  • 250 ml of any cooking oil 
  • 3 teaspoons of liquid dish soap.


  • Mix the two ingredients and store them in a bottle for future use
  • Whenever you need to spray take 2 teaspoons of this solution and mix with a liter of water
  • Put it into the sprayer and spray directly into the leaves.

#Recipe 2:- Three-In-One Insect Spray Recipe


  • 1 bulb of a small garlic
  • 1 small onion
  • 1 teaspoon of dry pepper powder
  • 1 tablespoon of liquid dish soap


  • Take the bulb of garlic and onion and make a paste of them in an electric blender.
  • Add the dry pepper powder into the paste. 
  • Then let this paste sit for a few hours.
  • Strain the mixture with a fine cloth.
  • Add the liquid dish soap and mix everything very well.
  • Now add some water and make 2 liters of solution.
  • You can keep this liquid in the refrigerator for up to a month.
  • Spray it on both sides of the leaves for better results.
  • Be careful while handling the mixture because it contains hot pepper. 
  • Wear disposable gloves while spraying to avoid skin contact.

#Recipe 3:- Neem Oil Recipe


  • 2 teaspoons of Neem oil
  • 1 liter of Water
  •  Few drops of liquid dish soap


  • Mix neem oil in water. 
  • Then add the liquid dish soap
  • Then pour it into the sprayer and spray it twice a week regularly.

#Recipe 4:- Orange Spray Recipe


  • 1 orange peel 
  • 2 cups of water 
  • Few drops of liquid dish soap


  • Boil the water in a pot and remove it from heat.
  • Add the orange peels in the steaming water and cover the lid of the pot 
  • Let it completely cool down
  • Remove all the peels and put this in the sprayer
  • spray this solution on your leaves when you notice insects.

Preventive Measure

Do not over-fertilize the Dahlias. Because the excess presence of nutrients attracts insects.

Do not spray insecticide during high temperatures. This can burn the leaves.

Encourage beneficial insects such as ladybugs, and lacewings. Because they feed off these harmful insects and don’t damage the plants.

3. Cultural Problems of Dahlia

Some management issues can result in brown and yellow leaves on the plant. 

Overwatering is one of them. When the soil is waterlogged and soggy the roots cannot breathe very well.

As a result, the root can take in less water and nutrients. Without water and nutrients, the plant becomes weak, and leaves start to turn brown and die. 

Overwatering can also encourage root and stem rot. 

On the other hand, underwatering also turns the leaves brown and brittle. When the plants are underwatered they cannot produce enough food. And this makes the leaves lose their green color and they turn yellow. As time goes by the yellow leaves turn brown and the plant starts to die.

Dahlias thrive in sunny conditions. But too hot weather can turn the Dahlia blooms into brown. Too much exposure to sunlight burns the leaves and also turns them crispy and brittle. 7 to 8 hours of sunlight is all they need. 

Control Measure

It’s necessary to have a good watering schedule to bring the Dahlias back to life. Use a moisture meter to check the moisture level of the soil to determine how much watering is needed. (Our pick: Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden)

You can also check the moisture of the soil with your bare hands. Just dip your fingers into the soil to guess the moisture present.

Water deeply 2 or 3 times a week depending on the weather conditions. Remove all the brown and dead leaves and avoid overhead watering. Add a layer of organic mulches to the soil. It helps to keep the moisture.

Once the water balance is restored the plant will be green again. Move the potted Dahlias in a shaded place in the afternoon if the weather is too hot. 


Brown leaves can be fixed easily if you take the proper steps at the right time. Always look out for symptoms of diseases and pests and apply proper fungicides and insecticides.

In this article, I have tried to discuss all the relevant information about the Dahlia leaves turning brown with their practical and effective treatments.

Share your experience about how you treated the brown leaves of your Dahlia. Because your experience can help give information to others.

Do let us know if you have any queries in the comments below.

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