Common Name(s): Saguaro

Synonym(s):

Family: Cactaceae

Native To: Common, central Arizona through southern Sonora, to 1100 m (3500 ft) in elevation

Native Habitat: Rocky slopes, sometimes sandy flats

Growth Habit: Large columnar cactus

Flowering: Primarily May-June

Distinguishing Characteristics: The saguaro is the only large single-trunked cactus in the United States. When young, they can resemble other cacti but can always be told by their short (as compared to those of barrel cacti) straight gray spines. The saguaro is also the only member of the genus Carnegiea, but other large columnar cacti can be found not far south of the border. The cardón resembles the saguaro but is even more massive, and produces flowers much further down the columns than the saguaro, which flowers only at or very near the apex of the trunk and branches.

Natural History and Cultivation Notes: The saguaro is Arizona's largest columnar cactus, representing a growth form that is much more abundant and diverse in México. Many westerns have been filmed around Tucson; this, in addition to its appearance on many "Old West" products, has given the mistaken impression that saguaros are ubiquitous. The saguaro, however, is found only in the Sonoran Desert, from southern Sonora to central Arizona, where summer rains provide needed moisture at the peak of stem growth. The large, white, waxy flowers each last just 24 hours. At night, bats visit the flowers for the nectar and serve as pollinators; during the day many additional visitors transport pollen, including the white-winged dove. When ripe, the fruits burst wide open displaying the bright red pulp and multitudes of tiny black seeds. The pulp serves to attract animals, who then distribute the seeds. Young saguaros are often found associated with shrubs or trees; these plants may serve as 'nurse plants', shielding the tender cactus from the harsh sun or occasional frosts until it's large enough to withstand such pressures. Even when adult, however, a saguaro can become sunburned if transplanted with its north side facing south. A slow grower, the saguaro takes three decades to reach sexual maturity and can live up to 200 years. By the time it reaches 4-5 meters, the plant is 50-70 years old and is finally ready to start developing branches. Flickers and gila woodpeckers build their nests in the stems of the saguaros; these holes are then used by may other creatures for nest sites, including the rare pygmy owls. The cactus forms a thick tissue to surround the burrow, and, as long as there are few enough such holes, remains healthy. These burrows are called saguaro 'boots', and can be found lying on the desert floor long after the saguaro that made it is reduced to a pile of long wooden ribs.

Ethnobotany: The saguaro has been and is extremely important to the people of the Sonoran desert. The fruits are produced each summer, regardless of drought, making it a timely resource to traditional desert dwellers. The delicious fleshy fruits are collected with long poles and made into syrups and jams; the seeds are made into a butter or used in cakes. The cactus has special significance to the Tohono O’odham tribe who value it so much that they base their calendars and some spiritual ceremonies on the reproductive cycle of the plant. They also use the juice of the fruit to concoct a mild wine used in a celebration to encourage the coming monsoon season. The saguaro’s dry woody ribs have been used in the construction of roofs and fences, and as hooks for retrieving fruits. Arizonan settlers have also revered the saguaro by making it the state flower and by planting it commonly within the cities and towns of southern Arizona.

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