Why Are My Azalea Leaves Turning Black? [4 Reasons]

Azalea plants are pretty to look at. That’s why it gets super upsetting to discover black leaves on them. 

But instead of sulking, you’ve to ask yourself- why are my azalea leaves turning black

Well, firstly, you’ll face this problem if you don’t provide the right amount of water. Also, using too much fertilizer can make the leaves black. Then incorrect lighting and temperature conditions are to blame as well.S Specific diseases can be another reason. Lastly, you’ll see black leaves because of insects too. 

Now, we suggest you have in-depth knowledge about the issue. Otherwise, you won’t be able to save the poor plant. 

Therefore, please stay with us and read till the end!

4 Reasons Why Your Azalea leaves Are Turning Black

We all want our plants to grow without any problem. However, sometimes they do suffer. And that’s usually because of our silly mistakes.

So, we’ve gathered 4 common mistakes that can result in black azalea leaves-

Incorrect Watering

The first and foremost mistake a houseplant gardener makes is- 

Providing too much or too little water to the plants. To be honest, this simple mistake is pretty harmful to your plant. Because incorrect watering can turn both azalea leaves black and mint leaves purple

Now, azalea plants require moist soil. However, they dislike being surrounded by water for a long time. 

But how much water an azalea plant needs varies from season to season. 

In summer, they thrive if the water is provided 1-2 times per week. During winter, they require water 2-3 times per month. If you don’t maintain this amount, your plant’s leaves will eventually become black.

Because providing too little water won’t help to keep the soil moist. Watering too much will surely make the soil soggy. Which will result in root rot disease and ultimately black leaves. 

So, did you provide the right amount of water?


Now, even if you’ve messed up with watering, you can save your azalea plant. 

Firstly, if you’ve provided too little water- 

You’ve to water the plant quickly. Keep watering till the water gets out of the drainage holes. 

Make sure to water at the roots as they are probably dried out. Let the plant absorb the water. 

Start watering again once the soil is dry. That’s why using a moisture meter will be really helpful in such situations.

So, use the meter and water again when you get a number 4 read!

Now, if you’ve overwatered the plant- 

You need to remove it from the present pot or container. And place it in another one. But make sure the pot you’ve picked has 3-4 drainage holes at the bottom. 

Also, while making the new soil for the plant-

Try using a specific potting mix that doesn’t hold water. 

Now, after replanting, wait for a few minutes to make sure the soil is dry. Because only then you can provide water. Remember to water the plant till water comes out through the pot’s drainage holes.

And that’s all you’ve to do!

Too Much Fertilizing

Yes, fertilizers do help your plant. But applying too much is problematic.

Because feeding plants too much fertilizer causes them to be sick. Therefore, it can be easily said that-

Over-fertilizing is a reason for not only azalea but also peperomia black leaves.  

Now, some of you might not know how much is too much. But we’ve got you covered. 

So, azaleas only need fertilizing when they grow new leaves and buds. Furthermore, you’ve to apply a fertilizer that’s perfect for plants that like acidic conditions. 

Also, using fertilizer every two weeks is labeled as over-fertilizing too. Doing this will most certainly help the black leaves appear.


Now, how to turn the situation back to normal? 

Well, first of all, you’ve to drain the excess fertilizer. For that, start watering the plant until the water escapes through the drainage holes. 

After that, let your azalea rest. Don’t use any fertilizer for about 2-3 months. 


Only apply half the strength of a phosphorus-rich fertilizer that contains iron. Because this type of fertilizer is great for plants that thrive in acidic conditions. 

Now, to reduce the strength-

Mix 1 teaspoon of fertilizer in 1 liter of water.

Wrong Lighting & Temperature

Your plants can thrive longer with the correct lighting and temperature. Otherwise, they’ll get sick and develop black leaves. 

Now, you might not know but-

Azalea plants are quite picky when it comes to living conditions. They like bright and indirect sunlight. Because high heat or direct sunlight can dry them out. And turn their leaves black. 

Plus lighting and temperature are kind of related. So, maintaining a decent temperature range is also vital. 

Azaleas thrive when the temperature range is around 50-60 degrees Fahrenheit. Too much or little and you’ll see your plant’s leaves turning black.


Now, what can you do to fix this situation? 

Well, it’s not that hard. You just have to relocate your plant. This time, pick a spot that receives indirect sunlight. And keep the plant there. 

This will surely help to achieve the right lighting and temperature conditions. You also have to check the plant’s temperature to be sure if it’s getting the right amount.

Fungal Diseases

Some specific diseases can cause azaleas to have black leaves too. Even though houseplants don’t suffer from diseases much-

They can still get infected.

Mainly two diseases are responsible for turning azalea leaves black. The first one is called Cylindrocladium blight. And the other is Rhizoctonia web blight. 

Now, these two can be easily identified by observing how the leaves are turning black-



Cylindrocladium blight

Leaves turn brown/black and eventually fall off within 3-4 days. Roots and stems can be affected as well.

Rhizoctonia blight

Small spots can be seen at first. But leaves become light brown to black real quick. The leaves will fall off quickly after turning black.


Now that you know which disease is to blame, let’s look at the solutions-

For Cylindrocladium blight, use a disinfected blade to discard the affected and dead areas. Such as leaves, stems. 

If your plant is suffering from Rhizoctonia blight, remove the dead leaves first. Then try controlling the disease by providing clean air and proper water. 

However, applying a fungicide can give better results. We suggest using fungicides that contain myclobutanil, chlorothalonil, iprodione, thiophanate-methyl, or azoxystrobin.

Specific Insects

Now, the last reason why your plant can get black leaves is insects or pests. It’s pretty easy to identify whether this is the problem or not. 

Because you’ll find insects such as azalea lace bugs on the leaves or surroundings. 

Now, lace bugs mostly lay eggs on the undersides of azalea leaves. And when the eggs hatch- 

New lace bugs start piercing through the leaves. And suck the chlorophyll out of those areas. Which leads the plant to have less chlorophyll than needed. 

Lack of chlorophyll makes the leaves yellow at first. Then eventually you’ll see black spots on the leaves of your azalea.


To save your azalea plant, you’ve to remove unhatched eggs first. For that, wear your gloves and start applying insecticides. 

We recommend using insecticides such as neem oil to get rid of the eggs. Also, don’t forget to discard the dead eggs afterward!


Question: Why are azalea leaves turning brown? 

Answer: Well, azaleas leaves become brown due to two reasons. Firstly, because of alkaline soil as the azalea plant likes acidic soil. Another reason is fungal diseases. 

Question: How to revive a dying azalea? 

Answer: First of all, you’ve to use a specific organic fertilizer. And this fertilizer is called fish emulsion. Then trying spreading compost on the root areas. Furthermore, use mulch to keep the soil moist. Also, don’t forget to water the plant properly. 

Question: How to treat black spots on azalea? 

Answer: We suggest neem oil to the affected area. This way, you can get rid of the fungal diseases that caused this situation. Make a mixture with 1 heaping tablespoon of baking soda, 1 gallon of water, and 1 dash of horticulture oil. This will help to treat the black spots.


Well, hopefully, you’ve got your answer on why is my azalea leaves turning black. By the poor drainage system can make the leaves black too.

So, why did your azalea suffer? 

Share your answers or any questions in the comment box. Best of luck treating your azalea leaves!

We will be happy to hear your thoughts

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