The azaleas planted 2 months ago are dying after the flower season. In early April some leaves become yellow and dry from the tip spreading to the center, but it was not severe. At the beginning I thought they were not watered enough. So I watered them twice a week. I also gave them a little fertilizer (Expert Gardener, plant food for Azalea 10-8-8, only applied half of the amount as described in the label). But after several weeks, the situation didn't improve only got worse. So is this a disease, a rotten root or a caring problem? There are new leaves growing so I guess perhaps it is not the root. Please help and thanks!

Type: Rebooming encore azalea, Autumn Carnation
date planted: March 4, 2024
Zone: 9, Houston TX
Planted in acidic soil with compost, elevated base with ~2 inch mulch
1-2 hr direct sunshine around noon, partial sun (with tree shade) in the afternoon.

I am not good at growing azaleas, but it looks to me as if your plants are recovering from whatever ailed them. Continue your recent practices and see how they do. All they should need at this point would be enough water to keep the soil moist.

Keep the mulch away from the stems. Azaleas are very prone to crown rot.

Thank you both! I will keep watering them, and move the mulch away from the main stem.

Azaleas have a very shallow root system so it is very easy to miss watering or to overwater them. Instead of watering as you are now doing, consider instead testing the soil almost daily instead at a depth of 4 inches and then water the soil if it is dry. Skip watering if the soil is already soggy when you irrigate. To ensure you are watering them sufficiently, use enough gallons of water to moisten the soil down at a depth of 8 inches. After watering, periodically test the soil at that depth, if the soil at a depth of 8 inches is dry after waiting for the soil to percolate, use more water when watering. If the soil is soggy, use less water. If the soil at a depth of 8 inches is always soggy after watering and waiting for the water to drain, investigate for water drainage issues. Maintain 3 to 4 inches of organic mulch at all times.

To test for root rot, very gently dig around the base of the shrub, looking for dark, mushy, or slimy roots. Healthy roots should be firm and white or maybe a light tan in color but should not foul smell. Sometimes, you may observe dark lesions or cankers on the stem at or near the soil line. You can also observe fungal growth in some cases.

Other things to consider. What types of trees are growing nearby? Look for pests like voles and stem borers. See if the plant shows signs of bark split due to winter damage.

Hi Luis,

Thanks a lot for the detailed instruction! When I watered them this morning, the soil was still wet at about 4 inches. Maybe I should water less.
The plants are close to oak trees. They do not have bark split - they were just planted outdoors this spring.
I looked into the root - they appeared brown and slim. They do not have a foul smell. I am not sure whether it is rotten or not. Can you tell from the picture?

They're buried way too deep. You should be able to see the top of the root flare. I would lift them out and add soil under to expose the root flare. They should be a little higher then the surrounding soil.

Healthy azalea roots tend to be pale or light-colored when young and may darken to a brownish color as they mature. However, if you notice that the roots are excessively dark brown or black, it could be a sign of rot or other issues.

To plant, place the root ball into the already prepared hole, making sure that the top one to two inches of the ball are above the surrounding soil. Then, pull in your humus/organic soil, pack it firmly, and top with mulch. Never put new plants deeper than the soil's initial depth. Make sure the mulch and dirt are removed from the exposed root collar. Buried root flares can cause collar rot in azaleas and rhododendrons.

Hi Lucy and Luis,

Thank you both for your advice! From the symptoms I guess maybe it is a rotten root with too much water/poor drainage. It rained continuously and heavily in my area not long ago. I removed mulches from their root. I will try lifting it up and see if it helps.