I'm in the Greater Cincinnati area. We've had hot, dry weather and very little rain, so I water things.
In front of my house is a small area about 12 X 4 feet with a red cedar in the center. I have had a variety of hardy plants there with no problems until this summer. I rooted out the iris and platycodon, trimmed the cedar for more light, and planted a dwarf rhododendron on one side, an azalea, Hershey's Red, on the other. I filled it in with wave petunias. First the azalea died, then the rhodo began. Around the rhododendron, the petunias died, but only a few. I have thriving blooms in the center now, and the tree is fine, but I lost all the plants on either side. Was it a virus or fungi? What can I do to assure healthy plants next year?

* * * *
Bob L

There is a disease that would effect both the azalea, and the rhododendron. It is a viral disease, with a soil born pathogen. It is pretty easy to tell if that was the case. The leaves on both plants would have rolled up tightly like a cigar and turned brown, then plants would have died. It should not have harmed your petunias however. It could be could be just a coincidence that the flowers died, by some other cause. If it was the viral disease that took out your rhododendron and the azalea, don't plant the same type of plants in that location again, for at least 5 years. Then only try a cheap one 1st to see if the pathogen is still there.
It is possible that the plants died from over watering, but I have no way of telling. It has been a very hot dry summer here as well, but also extremely humid, and the soil stayed damp for weeks after watering. Not to many insects will infect azaleas or rhodies ,at least to the point of killing it in one season. So I doubt that is the case. Also while both are very prone to developing leaf spot and anthracnose, those diseases usually will not damage those type of plants to the point of dying in one season.
One other possibility could be a natural gas leak, but that should have killed everything in the one area, and not left anything alone.
Hope this helps.

Mike

* * * *

Thank you for the replies. I figured it was something in the soil, a virus most likely. The heat and humidity didn't help matters. Yes, the cedar tree is fine, but I'm putting in a few cheap mums for the fall. This year in May and June, I had an ideal garden, but despite watering, spraying for leaf spot and mildew, I still lost plants. The dahlias simply shut down, tops died, but are sprouting out again. The miniature roses, however, are holding their own. What a year. 36 days of 90 plus degrees when our average is 4.
Thanks again.

Bob

* * * *
Bob L