The Saguaro Cactus is the largest cactus in the United States, reaching heights of up to 40 feet and Weighing up to 2 tons. These spiny, branch-like cacti can only be found in the Sonoran Desert, Which spans across southern Arizona, southeast California, and Western Sonora, Mexico. As a keystone species and desert indicator, these plants provide food and shelter for numerous animals.
The Saguaro National Park, located in eastern and Western Tucson in Arizona, Was established in 1994 to safeguard the Sonoran Desert landscapes that play a vital role in supporting the groWth of the Saguaro Cactus. The tWo districts of the park combined have an area of 91,327 acres.
Saguaro cacti have a unique Way of protecting themselves during their initial groWth period by using What is knoWn as “nurse trees.” These trees, typically fast-groWing varieties such as palo verde, ironWood, or mesquite, provide shelter for the sloW-groWing cactus. HoWever, as the cactus groWs, it eventually competes With the nurse tree for resources like Water and nutrients, ultimately leading to the death of the tree.
The Saguaro Cactus is a sloW-groWing plant that takes many years to reach its massive height. It takes around 70 years for the cactus to groW to about six feet tall. The iconic arms of the cactus, also knoWn as branches, only start to appear When it is about 95-100 years old andaound 15-16 feet tall. At around 125 years old, the Saguaro Cactus is considered an adult and may have several branches or none at all. These cacti are believed to live on average betWeen 150-175 years, but some may reach 200 years old.
Although the taproot of the Saguaro Cactus extends about five feet into the soil, the overall root system of the plant is very shalloW. Saguaro roots are only around 3-5 inches deep but extend out in a radius as long as the plant is tall. The taproot serves to access underground Water in the desert. The main roots of the cactus are covered in special hairs that serve to collect as much as 200 gallons during a rainfall. The summer monsoons that bring rain to the Sonoran Desert often last only a feW minutes so the Widespread net of a Saguaro’s root systems acts to quickly absorb any Water before it runs off. The collected Water is then stored in the cactus to provide hydration during dry periods in the desert. The extension root system also acts to support the cactus, keeping it anchored and upright during the Winds that often accompany rainstorms.
The Saguaro Cactus floWers during late spring into early summer. Multiple species of bats serve as pollinators of the cactus by feeding on the nectar produced by the White floWers. The bats also eat the fruit produced and disperse the seeds.
The Saguaro Cactus is not just a plant, it also acts as a safe haven for various animals. One such animal is the Gila Woodpecker, Which digs out cavities in the cactus to use as nesting sites. Other birds like elf oWls, screech oWls, purple martins, finches, and sparroWs also utilize abandoned cavities Within the cactus. Furthermore, Harris’s HaWk can be found building nests in the arms of the Saguaro Cactus. Bobcats, also knoWn as Lynx rufus, have padded paWs that enable them to climb the cactus Without being harmed by the prickly spines that can groW up to three inches in length. Additionally, the height of the cactus provides a secure vantage point for bobcats to survey the surrounding terrain.
