O.K., Bob finally rattled my chain
Richard's probably played around with them as much or more than I have. Like most folks that live in southern Arizona, palo verde ( means "stick green") has broad appeal as well as being the state tree of Arizona. They are not a long-lived tree; the blue palo verde, which favors desert washes, lives from 75-100yrs.; the foothills palo verde that favors steeper slopes and hills may live slightly longer. It's for this reason I've stayed away from them only because if you obtain an older one, you don't have much time to develop it before it's natural clock expires.
I think nursery stock is the way to go with palo verde and I know of several nurseries in Tucson that stock them. I'm with Richard about trying to dig them from the wild--forget it. There is one nursery in Tucson that goes out before they scrape the desert to develop home sites and they have crews of 4 guys trench a rootball and literally build a box down in the trench before lifting the tree and putting a bottom on the box. These boxes are 4' square and 4' deep and must weigh TONS by the time the tree and box are lifted out with a backhoe. No thanks!
Of the legumes Richard listed, Desert Ironwood, Olneya tesota, is by far the most intriguing in that it can live for centuries and has pretty purple wisteria-like flowers in June. You can sometimes find these in nurseries in southern Arizona too. Whatever your choice, I wish you luck in your pursuit of our desert natives
