Only one tree grows naturally in the great Sonoran desert that fills much of Arizona and continues down into Mexico. The dominant site throughout the desert is, of course, the huge Saguaro cacti.
Now that they are protected, they are everywhere, including dominating well-tailored back and front yards of suburban homes in and around Phoenix. You can’t cut them down, so no matter how well you plan your garden, nothing prevents a cactus from decided to take root there.
The ironwood is not a cactus, but a tree. It can live in the hottest, driest possible growing condition. It is the only tree that will survive in that environment without human intervention.
An old, gnarled ironwood tree is a true symbol of the North American west. Resilient doesn’t cover it. This is ultimate survival.