A couple of my rhodos are sick: One has lost most of its leaves last year, though it still put out a few blooms this year. It was probably a victim of drought, though keeping it watered doesn't seem to be helping. Any ideas? Another larger (15') rhodo ('King of Shrubs') on the opposite (West) side of my yard has suddenly started to look sick this year. It's leaves have yellowed significantly (bordering on brown), though it's still managing to put out flowers. The only thing I can think of that could be wrong with this one is that there used to be 2 mature fir trees on the other side of the fence behind it, but the #%^&!! developer removed them in early 2017. This changed their growing conditions to being well-shaded from the afternoon sun to full sun. Does anybody have any ideas (other than doing unspeakable things to the developer)? I don't want to undertake moving this rhodo, as it will create a snowball effect for all the shorter rhodos around it.
If not in fact sun burn then maybe powdery mildew - look up powdery mildew of rhododendron to find out how to check. Also lace bugs can produce similar damage.
Thank you. I checked for both of these things and I don't think it's either. No sign of lace bugs (no bugs, no poop) and no sign of powdery mildew (no powder and no spotting on either side of the leaves - just yellowing all over). I looked up sun burn and the colouring isn't consistent with that either (no different on north and east sides of plant than south and west sides, and the yellowing / browning doesn't seem to start at the center of the leaf. I'm going to dig around the base of the plants to look for root weevil larvae and possible girdling below the soil line. That's the only thing that seems to fit?
