If you're planting now in Kansas, be prepared to water twice a day for awhile; in fact, I'd suggest waiting a couple of weeks for actual planting. You can buy them now, and it's a good time to buy them because there are lots of end of season sales, but I'd suggest to keep them potted and in the shade until the heat wave disappears in early September.

ProfessorRoush (www.kansasgardenmusings.blogspot.com)

If the nursery is close enough, just tag the plants and pick them up at proper planting time. If you bring them home, keep them in the shade, or at least keep the pots shaded so the roots don't cook (when they're cheek by jowl in the nursery they protect each other). Water as needed which I check by lifting the pot. You'll recognize the difference between a watered and needs water pot by weight. Plant in Sptember-October. I plant nothing in August.

tj