I agree that your blue mist shrub, your phlox, and your echinacea are overwatered. I know you can't control rainfall, but could you turn off the hose where these plants are located?
The flowers on your butterfly bush need to be deadheaded/cut off badly - that many flowers going to seed all at once will cause your plant to go down fast. Buddleia/butterfly bush also needs good drainage - if the soil is water logged, it may die a slow death.
Sherry

One of the best ways to get better drainage in clayey soils is to add and encourage worms. Use a pitchfork or garden fork to GENTLY loosen the soil around the dripline of the plants, then lay a mulch of rich compost (partly decomposed hay, straw, leaves, etc) in a ring around the base, leaving a buffer between the ring and the stems.

Add redworms. Look in your yellow pages to see if there's a worm farm around; failing that, hit the nearest horse farm and ask for the edges of their old manure piles. Amazing how many redworms are in there! Take them manure and all.

Keep just damp but not wet. As the material they are in is consumed and decomposed further, they will burrow into the soil below for shelter...and then further and farther.

It really does help drainage...and the worms are fun anyway! The fact that they enhance the soil fertility is just a bonus. :)