The age of a cactus may be determined by measuring its height. In the case of the saguaro cactus, the most popular variety, it can reach up to an average of 40 feet tall in its lifetime.
The saguaro cactus that is typically seen in the Sonoran Desert of the American West can grow to be quite tall. In fact, the tallest of this type of cactus grew to be 78 feet tall. Looking at the height of the cactus is a way to determine its age. The cactus has several spiny "arms" that come off of its trunk, though the height is measured at the tallest part of it. It may take up to 10 years for this cactus to grow just 1 inch. By the time it is about 95 to 100 years old, the cactus will be about 15 feet tall. The cactus will reach its full height at around 200 years old, when it will be about 40 to 45 feet tall. It is the largest cactus in all of the United States.
The saguaro cactus is an important icon of the American West. It is especially important to the Tohono O'Odham tribe, who view the saguaro cacti as highly respected members of their tribe. They only will grow in southern Arizona, and they are native only to the Sonoran Desert. This cactus will grow anywhere from sea level to 4,000 feet in elevation.