The Saguro cactus grows only in southern Arizona and Mexico. It grows slowly, an inch a year. The cactus in the picture is old.An adult saguaro is generally considered to be about 125 years of age. It may weigh 6 tons or more and be as tall as 50 feet. The average life span of a saguaro is probably 150 - 175 years of age. However, biologists believe that some plants may live over 200 years. The human psyche takes a long time to grow too. Most humans don't make it to 125, but people are surviving longer and longer each year. The cactus is a model of us. It survives under harsh conditions. But it does survive.