On the top shelf in my little hobby greenhouse grows a giant. Though this giant is only 5 years old and, for now at least, 4 inches tall, it has the potential to get much larger. The plant is the saguaro cactus from the Sonoran Desert of Arizona.
The saguaro cactus (Carnegiea gigantea) is a superstar amongst the cactus family both for its storied existence and size. It can reach as much as 45 feet in height though 20 to 30 feet specimens with foot thick trunks are more common. During the first 75 years of its life, it grows as an unbranched column; thereafter, it begins to branch and forms the familiar shape we know. Saguaros often live to be 150 years old.
This cactus grows only in the Sonoran Desert, the driest desert in the United States that occupies 120,000 square miles of the southwestern quarter of Arizona, and adjacent areas in California, the state of Sonora in Mexico and parts of the Baja Peninsula. It occurs in areas receiving between 2 and 10 inches of rainfall per year but won’t grow in salty soils or along arroyos where floods might occur. While it tolerates frost it won’t survive where freezing conditions prevail.
Flowering begins when plants reach about 50 years of age.
