Answer: First of all, I would suggest you work with your county extention to determine more specifically what has caused the discoloration. Overwatering can cause it, and sometimes overwatering can happen due to a difference in the soil in the bed or differences in the drainage pattern within the bed, or due to inconsistencies in the irrigation system, for example. But there are also some diseases that can cause discoloring, as could poor rooting, or even planting too deeply. Once you know the reason you will be able to decide how to proceed. Unfortunately it is very difficult to diagnose this type of problem long distance.
In the meantime, avoid wetting the foliage unnecessarily. Clean up and remove any fallen foliage. Provide a layer of natural mulch over the root area; it should be applied in a flat layer several inches deep and should not touch the stems. Do not fertilize them now, and water only as needed to keep the soil slightly damp. Plan on erecting a wind barrier for them this winter. Check with your extension as soon as you can in case it is something that you can treat. Good luck with your rhodies!
Q&A Library Searching Tips