The saguaro, scientific name Carnegiea gigantea, is a large, tree-sized cactus species, which can grow to be over 20 meter (~70 ft) tall. It is native to the Sonoran Desert in the U.S. state of Arizona, the Mexican state of Sonora, and the Whipple Mountains and Imperial County areas of California. The saguaro blossom is the State Wildflower of Arizona.
The common name saguaro came into the English language through the Spanish language, originating in the O'odham language.
Saguaros have a relatively long life span. They take up to 75 years to develop a side arm. A saguaro without arms is called a spear.
The arms are grown to increase the plant's reproductive capacity (more apices lead to more flowers and fruit). The growth rate of saguaros is strongly dependent on precipitation; saguaros in drier western Arizona grow only half as fast as those in and around Tucson, Arizona. Some specimens may live for more than 150 years; the largest known saguaro is the Champion Saguaro. It grows in Maricopa County, Arizona, and is 13.8 meters (45.3 ft) tall with a girth of 3.1 meters (10 ft). These cacti can grow anywhere from 40 to 60 feet. They grow slowly from seed, and not at all from cuttings. Whenever it rains, saguaros soak up the rainwater. The cactus will visibly expand, holding in the rainwater. It conserves the water and slowly consumes it.