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Scientific: Carnegiea gigantea (Synonym: Cereus giganteus)
Common: saguaro
Family: Cactaceae
Origin: Occurs naturally in the 'banana belt' zones of the Sonoran Desert uplands, mostly on gentle slopes to steep hillsides.

Pronounciation: Car-ne-GEE-a gi-gan-TEE-a

Hardiness zones:
Sunset 12-13
USDA 9 (local arid regions only)

Landscape Use: A dominant focal point, strong accent, xeriscape. Because of their visual dominance in any landscape situation, they should be used sparingly and with much predetermination. A saguaro in a normal residential front yard will eventually grow much too large and be out of porportion for the space.

Form & Character: Strongly upright and erect cactus, a true Sonoran Desert icon, imposing, dominant, inspiring, immense.

Growth Habit: Evergreen, succulent and fibrous perennial. Saguaro is strongly upright to 25 feet, rarely to 50 feet, with arms which according to 'folklore' develop after 60 years, in reality it is sometimes sooner. Young plants are shaped like inverted bowling pins and survive the intense summer heat of desert ground surfaces under the canopy of a larger "nurse" plant.

Foliage/Texture: Trunk ribs numbering 12 to 24, clumped group of spines on ribs with central spine to 3 inches, terminal single meristems on trunks and arms are coated in a dense mat of white hairs; coarse texture.

Flowers & Fruits: White and yellow flowers that are mostly nocturnal. Flowers pollinated by bats, birds and insects. Fruits are red and edible.

Seasonal Color: Flowers in May and fruit in late summer.

Temperature: Tolerant to 28oF. Saguaro is a true benefactor of the Phoenix urban heat island.

Light: Full sun

Soil: Well drained soils are essential. Saguaro produces an expansive, superficial root system.

Watering: None once established. Irrigated urban saguaro are massively large. Engorgement, hanging limbs, stem failure, and toppling is a common problem of large specimens located in and around irrigated landscapes.

Pruning: None

Propagation: Seed

Disease and Pests: Bacterial ooze, treat by excavating infected area and applying a 10% bleach solution mixed with water (not alcohol).

Additional comments: Saguaro flowers are the Arizona State flower. Saguaro cacti are able to grow in the Phoenix Valley because of the Phoenix urban heat island which provides adequate winter nightime cold protection for this freeze sensitive taxon. The transplanting of larger specimens requires extreme care to maintain hydration, directionality of exposure and to not damage stem and trunk tissues. Mature specimens can weigh upwards of 8 to 10 tons. After transplanting larger specimens, a temporary scaffold support of 2 by 4 lumber is typically constructed to hold transplants specimens upright until established (sometimes for several years).

Various tidbits: Saguaro cacti received their botanical name after Andrew Carnegie who established desert lab in Tucson for native plant research. Saguaros can live to 250 years old, are protected in Arizona as endangered species. The relocation of mature native saguaro is regulated by the Arizona Department of Agriculture.

Ethnobotanical uses: Native Americans, particularly the Tohono O'odham people, used seed to make flower, fruit to make jelly and wine. State law restricts movement or sale of indigenous specimens without government permission. The skeletal structure of a dead saguaro makes a nice desert landscape ornament.