Double potting, with a 2-3" air gap or even styrofoam peanuts between the pots works pretty well. And, plant them where the pots can be shaded even if the plant itself is in sun. A front row of big-leaved, drooping plants can protect the others.

I "mulch" potted plants with a thick layer of pebbles, which lets me dump a lot of water on them fast and keeps the soil cooler. Rocks don't pass heat along.

Thank you for the advice! My mom says that she collected popcorn peanuts for doing this a couple of years ago but the wind got them and they were all over her property for awhile :) So I will have to watch how I store them. One thing I have found the more decorative pots good for is holding interesting rocks by themselves..... maybe I will try planting them with interesting whimsical garden art or something.