Saguaro Cactus

by Gage Patinella

The Saguaro Cactus, or Carnegiea gigantea, is one of the most characteristic plants of the Sonoran Desert.[1]  It is also the largest cactus in North America.[2]These cacti are large and tree-like, often—though not always—developing arms or branches as they grow older.  These arms grow upwards in the most distinctive conformation of all Southwestern cacti.[3]  The Saguaro grows slowly, maybe an inch a year, but to a height ranging from fifteen to fifty feet.[4]

The largest specimens, those with five or more arms, can date back hundreds of years.  An average one, however, possesses five arms and hovers around the thirty foot mark.[5]  Saguaros are pleated, allowing for expansion and contraction during the rainy and dry seasons.[6]  This expansion and contraction allows for the cactus to survive the harsh dry season.  A large saguaro holding its maximum capacity of water can weigh upwards of six tons.[7]  Along with the pleats’ considerable water storage capacity, the Saguaro cactus has an amazing root system.[8]  These monster cactus root systems consist of three parts.  One is a tap root that extends about three feet down into the earth below the plant, another is a thick root system which extends out about a foot in all directions, and the final is a thin root system that grows out radially from the cactus equal to the height of the plant.[9]  Saguaros are famous for the flowers they produce during the spring months.  During May and June, mature cacti bloom an array of creamy-white, three-inch-wide flowers with yellow centers.[10]  Clustered near the ends of branches, the blossoms open during cooler desert nights and close again by next midday.[11]  These blossoms turn a usually dormant desert plant into a vibrant one full of life and color.  It is this quality of the plant that has caused the people of Arizona to name it their state flower.

The Saguaro Cactus has a very finite and distinct habitat.  The cactus itself only grows within the limits of the Sonoran desert, in southeastern California, southern Arizona and northwestern Mexico.[12]  However, within that vast ecosystem it only occupies a small niche.  The two most important factors contributing to the growth of the cactus are water and temperature.[13]  They are generally found growing from sea level to approximately 4,000 feet in elevation.  Saguaros growing higher than 4,000 feet are usually found on sunny, south facing slopes where freezing temperatures are less likely to occur or are shorter in duration.[14]  One of the saguaros’ favorite types of habitat is rocky bajadas.[15]

With few trees in the desert, many animals make their homes within, or upon the Saguaro cactus.  Birds such as woodpeckers and gilded flickers make their nests within the fleshy pulp of the cactus while larger birds such as hawks, owls and ravens build theirs within the arms of the saguaro. [16]

Further Readings:

“Arizona State Flower.” 50states.com – States and Capitals. http://www.50states.com/flower/arizona.htm (accessed February 12, 2012).

“SAGUARO.” Biological Sciences home | School of Biological Sciences. http://www.biology.ed.ac.uk/research/groups/jdeacon/desbiome/saguaro.htm (accessed February 12, 2012).

“Saguaro Cactus Fact Sheet.” Arizona-Sonora Desert Museum. http://www.desertmuseum.org/kids/oz/long-fact-sheets/Saguaro%20Cactus.php (accessed February 12, 2012).

“The Saguaro Cactus And Its Greedy Guests ~ Kuriositas.” Kuriositas. http://www.kuriositas.com/2012/01/saguaro-cactus-and-its-greedy-guests.html (accessed February 12, 2012).

“Saguaro Cactus.” Pima County Government Arizona | Tucson, Marana, Ajo, Oro Valley, Sahuarita, Three Points, Arivaca. http://www.pima.gov/cmo/sdcp/species/fsheets/key/sag.html (accessed February 12, 2012).