Please see attached pictures. I just planted 12 rhodies, in the same place, same soil, same kind of mulch. One of the new plants (1 - 2 year olds) just got rings on their leaves. I used a very clean (sterile) technique when planting. I do not know what the rings are, if they are contagious, if it might kill this rhody, etc. Any ideas here? Should I isolate this one plant, try to control the cause of these rings, dig it out, dispose of it, etc? The underside of the leaves are a brown, reddish color (what I call a "bleeding" rhodie. Thank you very much.