Many times when bushes and trees dies there can be be fungal diseases involved. Particularly when they are weakened from old age, too much water or other adverse conditions.

So I looked up Azaleas and it seems that Phytophthora root rot can be a very common problem with them. This often gets worse if the soil has been wet, especially in combination with high temperatures.

There apparently can be interveinal chlorosis and also a little purple in the foliage, depending on the cultivar. This sounds a lot like what has happened to your azalea.
You can do a search about it, or you can read more about it here: http://www.ces.ncsu.edu/depts/...

A list of cultivars and their resistance to this disease: http://www.ces.ncsu.edu/depts/...

I think Phytophthora root rot is a strong suspect here, but even if it's something else, I think that it's best to not put a similar plant in this place for a while. The earth will be tired after growing one species on it so long and other pathogens can build up over time as well. Perhaps also it can be good to amend the soil a bit and raise the bed some, especially if you feel that it gets a little to wet at times.

Good observations William.

Were it me, I might even dig out and dispose of a lot of the soil and replace it with some well amended new sruff. Then maybe plant some annuals there. Or another species far removed from the Azalea/Rhododendron family.

William said:Many times when bushes and trees dies there can be be fungal diseases involved. Particularly when they are weakened from old age, too much water or other adverse conditions.

So I looked up Azaleas and it seems that Phytophthora root rot can be a very common problem with them. This often gets worse if the soil has been wet, especially in combination with high temperatures.

There apparently can be interveinal chlorosis and also a little purple in the foliage, depending on the cultivar. This sounds a lot like what has happened to your azalea.
You can do a search about it, or you can read more about it here: http://www.ces.ncsu.edu/depts/...

A list of cultivars and their resistance to this disease: http://www.ces.ncsu.edu/depts/...

I think Phytophthora root rot is a strong suspect here, but even if it's something else, I think that it's best to not put a similar plant in this place for a while. The earth will be tired after growing one species on it so long and other pathogens can build up over time as well. Perhaps also it can be good to amend the soil a bit and raise the bed some, especially if you feel that it gets a little to wet at times.

This past winter was very bad and this summer was hot and humid, though we had little rain I watered daily and the spot it's in always had poor drainage, mabye that really did the older plant in the symptoms you describe do match up.

keithp2012 said:

I watered daily and the spot it's in always had poor drainage, maybe that really did the older plant in the symptoms you describe do match up.

That may be the Bingo. While anything in the Rhododendron family likes soil on the moister side. They also have shallower root systems and do not like soil with poor drainage.

I would also point out the hot/drought summers of '12 & '13 stressed a lot of plants. Then the winter of '13/'14 was brutal and I think for you winter '14/'15 was even worse.

That is a lot of stress in a short period of time - particularly for an older shrub that may have been near its life expectancy anyway.

A lot of people including me lost a lot of plants, trees and shrubs over the past couple of years.

DavidLMO said:

That may be the Bingo. While anything in the Rhododendron family likes soil on the moister side. They also have shallower root systems and do not like soil with poor drainage.

I would also point out the hot/drought summers of '12 & '13 stressed a lot of plants. Then the winter of '13/'14 was brutal and I think for you winter '14/'15 was even worse.

That is a lot of stress in a short period of time - particularly for an older shrub that may have been near its life expectancy anyway.

A lot of people including me lost a lot of plants, trees and shrubs over the past couple of years.

My sister had a huge rhododendron that died this year too, and three years ago was in perfect health. It's funny because I have another azalea mabye 20 feet away and it's doing fine, but the soil drains better where it is so that probably explains alot.

keithp2012 said:

My sister had a huge rhododendron that died this year too, and three years ago was in perfect health. It's funny because I have another azalea mabye 20 feet away and it's doing fine, but the soil drains better where it is so that probably explains alot.

Oh dear, does she live nearby you? If so it does seem a bit alarming. Not sure if your other Azalea is of the same cultivar as the one that died, but I hope it's a more resistant one and I'm glad to hear it has better drainage .

While David's suggestion about replacing all of the soil is normally a good one and I agree on it, I'm afraid that in this specific case it may not be enough as spores could be virtually everywhere. I have had stump rot(can be several Phytophthora species) on some of my lilies the two last years, thanks to cold and rainy springs. These attacks, while not very serious and only affecting a small amount of plants have been a long distance from each other and they have also been in soil that has never had any lilies growing in them before.

Edit - spelling

My hunch is a combination of several things. My gut tells me a major factor has been stress due to weather. Over the course of the of the past 3 years or so, I have lost 3 Andromeda, 2 Rhodys and 2 Azalea. A couple of those could have been plant quality at the time of purchase - I buy a lot of "orphans" cause I am cheap and have such a large garden area.

So true David, today there are very few - if any - areas in the world that haven't experienced some sort of usual weather patterns. This of course causes all kind of problems to both wild and garden plants. In addition to the physiological stress this puts plants under, I think we overall will see much more of pests and diseases as well . Not a good combo.

The interesting thing to me is that Long Island where Keith lives had far more than average snowfall the past couple of winters, which one would have assumed would protect the azalea more from cold than previously. Then again there would have been a lot of snow to melt, plus Long Island had some major flooding from rain in the summer of 2014. Whether Keith's specific area was affected by these events I don't know.

Looking at the picture of the base of the plant raises a few questions in my mind. Firstly there are several branches that have been cut off. I'm wondering over what time frame, is this all in the past two years or has it actually been declining longer? A couple of branches are hollow. One cut branch has some staining on the cut surface although it doesn't seem to be around the cambium as far as I can see.

Anyway, if there's a chance Phytophthora could be involved, and we're not likely to know for sure without a pathologist examination, there are lists of replacement plants that are less or not susceptible, such as this one:
https://plantpathology.ces.ncs...