Brown Spots On Azalea Leaves | Causes and Solution

What Causes Brown Spots On Azalea Leaves

Most gardeners face a common problem with Azalea plants like me. The other day I was walking through my balcony and saw some brown spots on Azalea leaves like this:

So what causes Brown Spots On Azalea Leaves?

These brown spots on Azalea leaves are caused mainly because of a fungal disease named Colletotrichum Azaleae. You can see round brown patches on the infected leaves. Prevent it simply by keeping it out from direct sunlight and giving enough water.


When the leaves of Azaleas change color, it usually means something is wrong. Azalea leaves can change color due to pests, illnesses, nutrient deficiencies, soil issues, too much or too little water, sunscald, and cold harm.

When I saw my Azalea leaves having these brown spots, I rushed to my friend who studies Botanics. They helped me by giving me a thorough idea of why my Azalea leaves have brown spots.

I found many people on the internet asking the same question over the internet without having a proper informative answer. So, I thought, I can help you guys!

Why There Are Brown Spots On Azalea Leaves?

Colletotrichum Azaleae, a fungus that causes brown patches on Azalea leaves, is the most common cause. This fungus causes circular brown spots to appear on both the upper and below surfaces of diseased leaves, according to

Environmental conditions are another cause of brown spots on Azalea leaves. According to Gardening Know How, Frost damage, nutrient shortages, improper watering, and too much or too little light, can produce leaf discoloration. When determining where to place your plant, it’s critical to think about these alternatives.

My friend gave me this scholarly paper on this topic.

( This is the paper)

Both sides of the leaves have round to angular dark brown leaf markings. The patches may clump together, especially near the edges. The fungus sporulates on both leaf surfaces in moist conditions, and greenish-brown fruiting stalks can be visible. When severe, chlorosis and defoliation can occur.

Colour of The LeafCause
Red or PurpleFall colors
White, Gray, Silver, or Bleached OutPowdery Mildew/ piercing-sucking pests like lace bugs or spider mites
Brown Tips and ages or BrownFall color change not Enough WaterToo much waterRoot root fertilizer BurnPestsDiseases
Green with Brown spotsFungal leaf spotsLeaf Miners
Yellow with pale greenSoil, not acidic enough nutrient deficienciesDiseasesPests (Leafminers)Not Enough water

How Do You Treat Azalea Leaf Brown Spots?

Protect the plant from frost, fertilize it with nitrogen and iron, give it an inch of water per week, and keep it out of direct sunshine. Browning of the leaves can be avoided by adopting these steps.

If the dark spots on the leaves persist after taking these actions, Colletotrichum Azaleae is most likely to be responsible. 

The best way to prevent this disease, according to, is to fertilize and water the plant, surround it with mulch, and maintain a suitable soil pH level.

To enhance circulation, remove diseased leaves and trim the limbs.

What Can You Do To Prevent Your Azalea Leaves From Brown Spots?

According to Clemson University 2017, These are some of the management Recommendations:

  • Avoid frequent overhead irrigation
  • Remove fallen leaves, and keep leaves dry when watering plants. 
  • Apply approved fungicides to the undersides of leaves and make sure to spray during periods of high humidity to prevent serious foliage damage

Why Does My Azalea Looks Dead?

Azaleas can be infected with fungi that cause browning of the outer edges and other symptoms. Dieback is a fungal disease that causes fading and yellowing of foliage as well as the death of twigs and branches when it is provoked by stress. Brown margins, wilting, discolored, and dead leaves are all symptoms of this fungus. It’s possible that branches will die.

Should I Remove Leaves With Brown Spots?

A fungal or bacterial disease is commonly indicated by water-soaked black and brown patches on plant leaves and stems. Remove any soft, discolored stems or leaves and discard of them. Remove any decaying roots and repot in fresh potting mix in a container that is slightly larger than the roots remaining.


Why Are My Azalea Leaves Turning Yellow And Brown?

Yellow leaves could be an indication of stress caused by soils that are alkaline rather than acidic (Azaleas require acidic soil for iron). Alkaline conditions make it difficult for the azalea to absorb nutrients (especially iron) from the soil, resulting in the yellowing of the leaves.

Why There Are White Spots On Azalea Leaves?

An insect known as the azalea lace bug is to blame for the damage. They reside beneath the leaves, sucking away the green pigment and leaving a scattering of tiny white dots on the upper leaf surfaces.

How Do You Treat Brown Spots On Azalea Leaves?

Bayleton, Ferbam, Captan, or a copper-based fungicide can be sprayed on the leaves. Begin spraying at the conclusion of the blooming period and continue every two to three weeks until mid-June. Leaf and blossom gall has further information. On the dead tissues, the leaves are brown or bronzed, with tiny black fruiting bodies.

How can you bring a dying azalea back to life?

If your azalea is dying, you should use a fish emulsion to resurrect it. Spread compost over the root system and use a mulch to keep the soil moist. The leaves of azaleas may scorch if they aren’t watered and mulched on hot, dry days, and the plant will begin to fade.

Why Do My Azalea Leaves Curls?

When temperatures drop below 35 degrees Fahrenheit, rhododendron leaves cup and curl at the edges. At 25 degrees Fahrenheit, the leaves will be tightly coiled and begin to droop. This issue isn’t caused by insects or disease; rather, it’s a mechanism for the plant to conserve water in its leaves during cold, dry, windy conditions. When the weather heats up again, the plants should recover.


As you know, you really no need to worry about your garden if you have the right knowledge about your plants. I’ve tried my best to clear your confusion and give you enough information about Brown Spots On Azalea Leaves. 

You can also find some other diseases related to your Azalea plants. You can look them up and seat back relaxed.

I guess you are now good to go! Go and take good care of those mini green friends of yours!

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