Mention "desert" and most Americans will likely think of saguaros. These tall, branched cacti are an indicator species of the Sonoran Desert, which extends across southern Arizona, through a sliver of southeastern California and into northwestern Mexico.
Favoring elevations between 2000 and 3500 feet, the saguaro is one of the slowest growing and longest lived plants in North America; reaching a height of 3 feet in its first 30 years, the main trunk begins to branch by age 65 and a healthy adult plant may live to be 200 years old. Its thick frame is supported by woody ribs while its pulp, coated with a thick, waxy skin and rows of 2-inch needles, expands and contracts with the seasons. Despite its meager, shallow root system, this cactus absorbs massive amounts of water during the monsoons of summer and is able to tolerate prolonged periods of drought. Some saguaros mature with a distorted, fan like (montrose) growth pattern; this may represent a genetic variant or result from an acquired condition (frost or insect damage).
Clusters of tubular, white flowers develop at the tips of the trunk and branches in May and June; opening at night, they are pollinated by bats, doves and a number of insects. The red fruits of the saguaro, pulpy and sweet, are consumed by a wide variety of wildlife and were a staple food source for Native Americans. The abundant seeds are spread across the desert via bird and animal droppings where a small minority, protected beneath shrubs, will germinate and begin their slow, steady growth. As adult plants, the large cacti may fall victim to winds storms and may become home to a host of creatures; gila woodpeckers and gilded flickers open nest cavities in many of the saguaros, later used by elf owls, ferruginous pygmy owls and a variety of small mammals.
