Plant gets about 6 hrs of sun daily, and is watered daily by sprinkler system.
It is very hard to say without seeing it, but I would have to guess that it has to do with being overwatered.
If this is on a daily sprinkler, regardless of how dry or wet the soil is at the time, then it will be watered when it is already wet. This will cause an infection and the symptoms that you are seeing.
You will want to let the ground dry down to at least 2 or 3 inches before watering again. This can help prevent infections.
I would also use a fungicide. This article will help: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
You can also apply 1/3 cup of DOLOMITIC LIME and a Tablespoon of WETTABLE SULFUR. These two can help kill off an infection in the soil.
Sometimes, if this is direct sun, the plants can be a bit sensitive to full sun. If it has done well in the past, then it shouldn't be of much concern, but it can make them a little more susceptible to disease.
This article will help you to care for you plants: https://www.gardeningknowhow.com/ornamental/shrubs/azalea/azaleas-noteworthy-shrubs-for-any-garden.htm
There are dark brown spots on my leaves and yellow discoloration. It’s all around. Not from just one branch. I have my first blooms for the end of summer- beginning fall.
It could be algal leaf spot disease, which is easy to remedy. Here is more:
https://www.gardeningknowhow.com/plant-problems/disease/algal-leaf-spot-control.htm
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/common-azalea-problems.htm
Should I deadhead Azaleas and, if so, When?
You can cut back your azaleas after they bloom to tidy up, reshape or rejuvenate the shrubs. Do not trim them any other time during the year or you may cut off next year's blooms.
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/pruning-azaleas.htm
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/azaleas-noteworthy-shrubs-for-any-garden.htm
Can I prune them in the late fall and what is the method I use? Thank you! AW
The plants will have their individual preferred pruning time, and methods. These articles will help:
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/pruning-azaleas.htm
https://www.gardeningknowhow.com/ornamental/flowers/roses/pruning-roses.htm
I'm new to gardening.
It's very important they have acidic, well-draining soil. You can get a soil sample through your local extension office and find out what the pH level is of your soil. They can also tell you how to amend the soil if needed for acidity.
These articles should help:
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/fertilizer-for-azaleas.htm
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/winter-protection-for-azaleas.htm
Hi! Can you tell me please my Deciduous Azalea Fireball plant has still got its leaves, even though its now the 6TH November? I planted it in August 2017, and it flowered really well this year May-July. Last year its leaves had fallen by the end of October. Thank you. Regards Rob
It probably is related to the weather you are having this year. I would just enjoy having leaves longer. I'm sure they will eventually drop.
Hi! I planted a Deciduous Azalea Fireball plant last year in August, but this year it's still not lost its leaves. Last year it lost all its leaves by the end of October and this year it flowered at the right time May-July. Can you give me some info please? Thank you.
If your azalea is otherwise healthy, I don't believe you have any cause for concern. Some deciduous azaleas remain evergreen during winter seasons with warmer than average temperatures. Plus, the late leaf drop may be weather related. Have yours produced colorful fall foliage yet?
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/winter-protection-for-azaleas.htm