Hey there! I'm in zone 6b, too, on the dry side of Oregon. We did the same - planted lots of rocks (because we have a ton of it around here!) and planted native high desert plants between the rocks. We have focused on native plants to ensure we're not bound to watering like crazy. We watered to get plants established that we brought in. We also allow for native "volunteers" :)
I've had great success with flowers and shrubs like Oregon grape, Indian blanket flower, penstemons, Cali poppies and other native plants. The best part is that my water needs aren't through the roof since everything I grow does well here.
Have you found any native nurseries in your area yet? That's a really great place to start - that and your state extension office. Best of luck!
