I wrote a few days back concerning a couple of sick rhododendrons. I took the advice of the Mr Henning and dug out and removed the top 4 inches of soil together with the mulch. Though the roots looked healthy the soil was heavy and somewhat compacted.
I pruned back the worst parts of the shrub. I replaced the soil from the tips of the roots to about 6 inches out with some store-bought top soil, mixed with the darkest stuff from under my pines and added
1/2 pint of vinegar for good measure. I applied this soil and spread a thin amount up to, but not touching, the main trunk.
A good watering in followed by brand new mulch and a mere 3 days later the difference is amazing. The plant has thrown up green leaf buds, is perkier, and in general looks worlds better. The brown leaves are no longer noticeable and I swear they look like they have healed themselves, but I know this cannot be true.
Of course I changed too many variables to identify which one was the problem, but the main thing the plants are doing well.
Anyway, thanks to Mr Henning for suggesting that I look deeper than the symptoms and hopfully these plants will make it, now.
Gary