Origanums will cope with that spot, and there are a variety to choose from. There are some prostrate ground covering Grevilleas that are hardy in zone 8a, not sure about 7a though, but they never need watering and flower for a long time. Can you grow California Poppy (Escholtzia), I think they would tough out the slope. Any hardy succulents would be good. Some ground cover roses are amazingly tough too, especially the newer lanscaping ones.
