Every one of my acid loving plants has started to turn yellow, a condition called chlorosis that usually means the soil is not acid enough to allow them to absorb iron. I had applied HollyTone and sulfur to the base of each earlier in the season but my next door neighbor pointed out that the roots have probably spread out further and the feeder roots are hitting our limestone soil. I've scratched the mulch away and applied the same mix at the drip line and watered it in. I hope that's the only problem. My native azaleas, mountain laurels and blueberries are all affected.
I think this is working. At least some of the plants are starting to green up again!