What do I need to use for saliva greggi (Furman's Red)?

I built a 40 something feet foundation plant facing south and wanted something easy. I didn't exactly till or anything, there is grass (rye grass which was temporary) underneath the stuff that i dug out to make a shallow trench for the rocks as border. The soil is a mixture of limestone rocks and a bit of clay.

I don't feel like amending it all that much and it sounded like salvia greggi would be something easy to grow. I figured compost and mulch over time will improve the soil so i was just going to make ugly hole and plant s. greggi. Will they survive alright?

I've planted Hot Pink just to see how it does and it thrived in limestone rocks and sand soil without me doing anything in the middle of the summer. So that's why I wanted to grow Salvia greggi in that bed at least for now.