is rich and acid, In Vancouver, BC, where I live. The mild northwest coast climate also helps, for sure, since we don't really have snow in winter, except very occasionally, and it doesn't last..
I understand from one of your postings, on Houzz, that you live in a 4-5 climate zone. We are in a 7-8 zone
years ago, and they are still fine it's a good sign. You are probably doing the right thing. You have to be patient though. I started planting my hydrangeas, 22 years ago, with the latest ones being planted seven years ago. As for the rhododendrons, they were already there when we bought our house.in 1990
years ago, and even since, they are doing so much better.
Love the Red Rhodedendron and hear they are easy to grow in the shade.