Here's something I'm noticing at my clients' properties. Plants, especially in sunny areas, are rotting out at the base from too much moisture. With the brutally hot summer we've had, the temptation is to water, and water, and water. Just because a plant is looking a little wilty, doesn't mean it needs water. Hydrangeas are some of the worst complainers about heat, and they WILL look floppy in the middle of the day when the temperatures are soaring, even if their roots are soaking wet. Watch to see whether they rebound in the cooler evening and morning temps.
Sedums/succulents as well as ornamental grasses are other areas where I'm seeing a lot of rot. These are fairly drought tolerant plants, and don't appreciate a one-size-fits-all approach to watering. Your annuals might need watering, but don't turn on the sprinkler system and water everything at once. It's important to check the soil moisture first before watering, and consider the needs of individual plants.