The iconic symbol of the America desert is a tall cactus with bent arms growing out its sides. This cactus is known as the Saguaro Cactus (Carnegiea gigantea), and the only place it grows naturally is in the Sonora desert which covers part of Arizona, a little of California, and some area across the border into Mexico.
The Saguaro Cactus is a very slow growing cactus and only grows 1 to 1.5 inches in the first eight years of its life. Growth rates vary depending on climate, precipitation, and location, but generally Saguaro Cacti start growing arms when they reach 50 to 70 years old and it can take as much as 100 years in lower elevations. However, the average life span for this cactus is 150 to 175 years, and it can live to a ripe old age of 200 years. The Saguaro Cactus is the largest cactus in the United States and normally grows about 50 feet tall, but the tallest saguaro cactus on record measured at a whopping 78 feet tall.
Like many desert plants, the Saguaro is a master at surviving in the harsh desert climate. It is covered in sharp spines to prevent animals for munching on it, and it can go without water for months at a time. To get all the water available in the soil the cactus sends down a large tap root about 2 feet into the ground. It also has a network of smaller roots that grow a few inches below the surface to catch any water during a heavy rain. A Saguaro is made up of plates which expand like an accordion as the root system draws up as much water as it can hold. The plant saves the water and slowly contracts as it uses it as needed, which enables the plant to go without another drink for months at a time. Because the majority of a Saguaro Cactus is made up of water, a full grown cactus can weigh as much as 6 tons. This intense weight is supported by a skeleton of interconnected wood ribs which is similar to the rebar used to strengthen cement structures in modern construction.
Saguaros produce waxy white blooms in late spring and early summer which bloom at night and close again the following afternoon. The flowers produce large amounts of nectar that attract bats which pollinated the flowers when they come to drink the nectar. After the flowers are pollinated, sweet red fruit develops which is eaten by many forms of wildlife and by people.
Occasionally the growing tips of saguaro cacti grow in odd mis-shapen forms which are referred to as crested. These fan-like growth structures are somewhat rare, and scientists are still unsure what exactly causes this phenomenon. Some think it may be a genetic mutation, and others think it may be a result of lightning strikes or freeze damage.
Lots of people like to grow cactus in their yard and as a result there is a lot of money in growing and selling cactus. Some people trying to make a quick buck will go out to the desert and dig up some old cacti to sell, and for this reason the Saguaro Cactus is protected by law. In the state of Arizona it is a class 4 felony to remove or destroy a Saguaro Cactus without permission from the landowner. But even with the laws protecting this cactus it seems to be able to take care of its self, and can even be deadly.
There is a story about a man named David Grundman who accidently killed himself with a Saguaro Cactus in 1982 near Lake Pleasant Arizona. Witnesses say that David fired several times with a shot gun at a 26 foot tall Saguaro Cactus at very close range, and a 4 foot limb of the cactus broke off and fell on him, crushing him. I don’t care who you are, that would be a painful way to go.
If you want to see one of the best stands of Saguaro Cactus, visit Saguaro National Park near Tucson, Arizona. http://www.nps.gov/sagu/index.htm