Steve - How about salvias? I have a Purple Rain salvia that has quadrupled in size since I bought it. I bought it as a 1 quart pot 2 years ago. I treat it VERY xerically.. hardly EVER watering/feeding it and it lives in rocks. It's now about 4' across and produces these beautiful purple flowers that last for weeks. You can also go with Little Trudy neptia (catnip)... I have wild catnip that grows like friggin' weeds here, so I'm not about to plant more, but I know that Little Trudy is very xeric & grows well in rocks, too.
Here's Purple rain Salvia (I don't have pictures of mine)
http://www.plant-encyclopedia....
I'd also mix in there different Speedwells (
http://www.bgperennials.com/in...) They do quite well in a xeric environment as well.
Of course, you can throw in some Silvermounds as well. But, be warned: they get HUGE!!! (
http://njplantsandtrees.com/in...)
These are all plants that I know work well in rocks, in a xeric (ie: no water 'cuz I'm lazy), and HOT (well, not 100+ but my altitude would compensate) environment, plus they all survive my winters just fine w/NO protection. Plus they (well, maybe not the purple rain, but if you want one, I can definitely send you a cutting) are all readily available at Home Depot/Lowes.
