(WZZM) Blooming Althea is one of Greenthumb Rick Vuyst's favorite this time of year. It's slow to leaf out, but Rick says right now they look great, especially in this extreme heat.
Phlox is another plant that flowers and loves this heat although it may have a little trouble with powdery mildew. There are many new varieties of Phlox Paniculata that are much more resistant to mildew. Rick says you should avoid planting near a wall or rocks because they could suffer from the re-directed sunlight. That's a reason why Rick doesn't love stone mulch.
One more that's thriving right now is Coleus. It has been adapted to take the heat. It used to be only for shade.