I purchased a Lewisia Longipetala which I was told at the nursery that it was a succulent. However, I was told by another nursery that it was perennial that was California Native. I plan to plant this plant in clay pot, but was advised that soil should be gravely. Should I plant this in cactus soil or should I pot in well drained potting soil with sand or gravel added to soil. Every book I have read makes no mention of this plant being succulent nor have I found what I type soil I should use. Any and all help appreciated.