Q.Rose of sharon
We have two rose of snow at the back of our house about eight years old. amjoyOne has wilting leaves and dying the othe healthy.
Soil is clay, and lots of rain this month

In some cases with rose of Sharon, they need a heavy rejuvenating pruning to get back to growing well. In this case perhaps the rain water is hanging around the root base too long and drowning the shrub. Clayey soils can form a swimming pool of sorts around root systems. Some, even the same, shrubs deal with it better than others. If you can create a drainage path away from the shrub affected, that may be a big help. Digging a trench on a downhill side of the shrub that is 2 to 3 feet deep and about 12 to 15 feet long, fill halfway with 3/4 gravel, cover with a landscape fabric and fill in with gravel and dirt mix. This will create a drainage pathway to help take water away from the root system. Here is a link to articles on Rose of Sharon care and growing for you as well: https://www.gardeningknowhow.com/ornamental/shrubs/rose-of-sharon/