Pronounciation: Car-ne-GEE-a gi-gan-TEE-a
USDA 9 (local arid regions only)
Landscape Use: 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: Erect cactus, Sonoran Desert icon, imposing, immense.
Growth Habit: 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 (Arizona State flower) 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. A true benefactor of the Phoenix urban heat island.
Light: Full sun
Soil: Well drained; 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.
Propagation: Seed. Transplanting of larger specimens requires extreme care to maintain directionality of exposure and to not damage stem and trunk tissues. Temporary scaffold support constructed of 2 by 4 lumber is often used to hold transplants upright until establishment.
Disease and pests: Bacterial ooze, treat by excavating infected area and applying a 10% bleach solution mixed with water (not alcohol).
Additional comments: 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. 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 as endangered species, and can weigh as much as 8 to 10 tons when mature. 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.