Does the native soil in the rocky area drain well? If so, mounding up some soil (use a lot of sand, adding it to whatever soil you plan to use if it isn't already very fast-draining sandy soil) might work. Russian sage needs very well-drained soil. You'll need a plan to hold the mounded soil in place so it doesn't wash away/erode in heavy rainfall.

It DOES drain well. You know, it's pretty good dirt (though still haven't gotten it tested yet--on to-do list), what there is of it between and around the rocks! Just for kicks, I went out to my proposed rock garden a few days ago--there are numerous rocks of enormous size jutting out in that part of the yard--and stuck the shovel in a few places--I didn't find any places that had more than maybe six inches of dirt before I ran into solid rock. . . some places only 2-4 inches! Some darned big rocks there! They're the equivalent of ice bergs in the ocean, in my mind. So we'll get some more dirt and amendments for that project. And then to think that someone actually hauled in MORe rocks--river rocks for the tiered beds just to the south of the house! AND all the gravel in the driveway. I can hardly wait to get that river rock out! I think I may use it to make a "dry creek" bed running through some part of the yard. I've read a few threads here about rock "mulch," and see nearly everyone has the same opinion about it that I do. Blach. Any other ideas about what to do with the river rock? (The top bed is about 8 feet wide and 30 feet long, the next tier about 5 feet wise, same length.) A lot of river rock.