Carnegiea gigantea
Family: Cactaceae​
​Common Name: saguaro
​Origin: The saguaro is endemic to the Sonoran Desert, spanning southeastern California, southern Arizona, and northern Mexico. It inhabits desert slopes, flats, and rocky habitats under 4000 feet in elevation.
Description: Carnegiea gigantea is a green columnar cactus with a single trunk, bearing 2-10 stout, upward curving branches covered in large pronounced spines. From early spring to summer, showy, tubular white flowers will form, followed by red fruits.
  • Interesting Features:
    • The saguaro is the largest cactus in the United States, reaching 50-100 feet tall and 6-10 feet wide.
    • The white inflorescence is the state flower of Arizona and only blooms at night, closing again the following afternoon.
  • Uses: The Tohono O’odham people use the saguaro flowers, fruit, seeds, thorns, burls or boots, and ribs for food, shelters, fencing, fiber, trade, and in ceremonies.
    • Other tribes have been documented using Carnegiea gigantea for food, medicine, ceremony, fiber, and trade, including the Western Apache bands, the Hualapai, Yavapai, Maricopa, Pima, Seri, and Yuman-speaking people.

Cultivation and Care:
  • Watering: Low
    • C. gigantea requires very little water, only needing to be watered occasionally during the growing season, and not at all during monsoon season.
  • ​Soil: Plant in sandy, gravely, and well-draining soil with a pH between 6.1 and 7.8.
  • Lighting: Provide full sunlight for the best growth. However, young saguaros should be given partial shade, especially during the summer, to prevent sunburn.
  • Propagation: C. gigantea can be propagated through seed or by softwood, hardwood, and semi-hardwood cuttings.
  • Cold Tolerance: 10°F, USDA hardiness zones 8a to 11.
  • Special Accommodations: The saguaro cannot withstand prolonged temperatures below freezing, and must be protected from intense frost.
    • Additionally, as this species is very slow growing, it may be necessary to buy from a nursery rather than propagating by seed.
    • C. gigantea is protected by law and requires government tags in order to purchase or transport specimens.

Sources:
  1. National Park Service
  2. The University of Arizona Campus Arboretum
  3. Wildflower Plant Database
  4. United States Department of Agriculture
  5. Tucson Cactus and Succulent Society
  6. Dave’s Garden
See this species in the Mark Dimmitt Desert Plant Conservatory Virtual tour