The saguaro cactus (Carnegiea gigantea), with its distinctive "arms," is perhaps the most recognizable of all cacti. Yet it is not a common cactus. It only grows in the Sonoran Desert in southern Arizona and western Sonora, Mexico, and one of the best places to see it is the Saguaro National Park, just west of Tucson.
The saguaro is a long-lived and slow-growing cactus. It can reach 40-60 feet tall, but takes a long time to reach that height. A 10-year-old saguaro may only be 1.5 inches tall. Under the right conditions--the right mix of water and temperature--they can live up to 150 or 200 years. As they mature, they often (but not always) produce branches or "arms" that tend to reach upward. A fully hydrated, mature saguaro can weigh more than 3000 pounds and is covered with protective spines. Although they are considered trees, they are much more fun to photograph than to climb. One day, I'd like to return and photograph these giants at sunset.