Hello, hawleyk33. Does your soil drain well? Can you clarify how much water it is getting? Can you check the fallen leaves for fungal issues?
Sometimes "plenty of water" is the problem. Too much water can cause root rot when the shrub gets a lot of water and-or has soil that does not drain well. If you insert a finger into the soil to a depth of 4"and it feels wet, not moist, that is a warning sign. Another way to test is to grab a handful of soil with one hand and squeeze. If you get a lot of water, you are either watering too much of the soil does not drain well.
When a plant develops root rot, it cannot absorb enough moisture for the leaves and these react same as if they were not getting enough water.
Also, check for pests especially if there is leaf curling involved so you can rule out that as a cause of the problem.
Finally, check for powdery mildew problems. It is common in July. Affected foliage eventually develops a white powder look, turns yellow and falls down. Older leaves are affected first.