It's been very dry here the last month or so too. We had decent rainfall most of summer, but in mid August it cooled down and dried up.
I grew all my Salvias in containers this year, and it seemed they needed a lot of water. Of course, I did have the containers rather crowded, but I did think they'd take it without wilting so easily.
I WSd 3 containers of Petunias, some saved from 'Laura Bush', an heirloom selection, some saved from lavender large flowered hybrids, and some pelleted purchased seed from the swap. None of the pelleted seed germinated, but several of each of the saved seed did, especially 'Laura Bush'. The hybrids reverted to some heirloom looking ones and 1 dark purple.
I think with Petunias, I'm just going to pick up a few Wave types from the greenhouse and grow them in containers. Now that I've tried a few, I want to have them cascading all over the front porch. They'll hide ugliness there really well, LOL.