Amy T
Amy T
  • Hometalker
  • Orlando, FL
Asked on Dec 10, 2011

I have a 40 ft row of mature azaleas under oak trees.

Douglas HuntFlowerscapes Garden Design & LandscapingThe Landscape Guy-Atlanta & North GA
+1

Answered

A year ago the middle plant started declining (wilting leaves and the branches died one by one). The problem was a leaky sprinkler and was told the excess water caused some kind of fungus or rot. I fixed the sprinkler. Now other plants 10 to 15 feet from that one look wilted. Could this fungus or root rot have spread?
4 answers
  • Mike and Anne
    on Dec 10, 2011

    Mature oaks and mature azaleas are not always compatible. The oak leaves can make the soil too acidic so you may want to get a soil test done to see if an application of lime is needed. There could also be a problem with too much shade and not enough air circulation around the azaleas as the azaleas have gotten larger and the shade canopy of the oak has expanded. Oak trees usually compete with the azaleas for the water available so even in the coastal areas of North Carolina we see azaleas growing under Live Oaks if the tree canopy is open enough for some light.It is possible the "root rot" fungus contaminated the soil but I think there is a higher probability of "old age" and air circulation causing the problem.

  • Mike and Anne-we usually avoid lime like it's a plague near azaleas in the ATL area...or anything to raise the alkalinity of the soil-are soil conditions different where you are? We tend to strive for more acidic soil for azaleas in these parts.

  • It is hard to compete with the roots of mature trees, especially oaks and maples. If you had a drought last year, that could be a clue. But you said the first one was from a sprinkler. You can dig one to see if the roots are growing around each other. When the roots are girdling, they can choke nutrients off from the plant.

  • Douglas Hunt
    on Dec 12, 2011

    It is possible the leaky sprinkler led to Phytophthora root rot, although that is not as common in our sandy soils as it is in heavier soils. Wilting leaves that resemble drought stress is definitely an indicator. It is difficult to control and you may have to use a fungicide. To confirm, I would try to take a leaf and soil sample (from around the roots of an infected plant) to your local cooperative extension office. There is one on South Conway. Good luck!

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