Anemone Pulsatilla
Draba Rigida
Campanula Rotundifolia

Should I use cactus potting soil? Or should I make layers or different soil? I read somewhere I should put sand on top and regular potting mix in the bottom, with gravel on the very bottom to further improve drainage. But what do they mean with "sand"? Do they just mean cactus potting soil?

If it's real sand, can you tell me where I can buy it, because I am sure it must be some kind of fertilized sand. Do they sell it at the Home Depot or Lowes?

Most importantly, my zone is Z8a, in the Dallas area.

Thanks!

Campanula rotundifolia seems to like more fertile, and open ground, at least way up here in Minnesota. It grows here abundantly in the cracks of basalt outcrops, where typical compost materials collect. But it too must be very adaptable, as its distribution is circumpolar.

Draba rigida I have only grown in troughs, in rocky alpine soil - excellent drainage and low fertility. But I can't say what it would adapt to.

More troublesome is the heat you have. Alpines don't like it. You will have to grow them in part shade.