Have you ever heard of Hugelkulture? It's basically burying logs then planting over the log/dirt mound. (Google it & you'll get tons more info.) The biggest advantage for our area is that it is supposed to cut down on watering as the wood soaks up moisture and releases it slowly.
Here's a pic of our first HC bed being built. I dug a hole about a foot deep then gathered up wood to stack in the hole. Next I'll pull dirt on top of the wood and we'll be good to go! Have you heard of Hugelkulture? Have you tried it? I'd love to hear your thoughts on this technique.