Is it sunny or shady? Or a little of both? How deep are the wires? Are we talking three inches or three feet? Are you in zone 8?
That info would make it easier to suggest a few things. I'm in NC (zone 7). Salvia and Vinca are nice perennials that are supposed to be drought tolerant, but do well in my wet yard (even with the drought the ground stays pretty wet).
Do you have a local garden nursery? Usually the employees are really knowledgable about gardening locally-- more so than the big box stores.