Carnegiea gigantea

An evergreen tree cactus reaching 10m tall and 4m wide, growing slowly, hardy to UK zone 9. The saguaro features a stout single trunk with upright arms and lacks glochids. Flowers appear in late spring to early summer (typically May–June) and are pollinated by bats, birds, and insects. It thrives in light sandy or medium loamy well-drained soils with neutral to mildly alkaline pH, requires full sun, and tolerates drought.

Description

A giant cactus. It is erect and like a tree. It can be 15 m tall. The trunk can be 60 cm across. The plant can weigh many thousands of kilograms. There are 12-24 ribs with spines grouped about 2 cm apart. There are 12 or more spines in a group and they are 2 cm long. In the centre there are 3-6 brown spines which are 7-8 cm long. The flowers are at the ends of the branches. The flowers are white in the centre and green on the outside. They are about 12 cm across and long. The flowers come out at night. The fruit are up to 8 cm long. They have red pulp and shiny black seeds.

Edible Uses

The fruits and seeds are the main edible parts, together providing a high-calorie, high-protein, high-fat food. Fully ripe fruits are red within, with a sticky, sweet pulp surrounding many small, black seeds. The flavour is sweet and fruity, often described as a cross between watermelon and fig, with no bitter or resinous overtones. The seeds are pleasantly nutty with a subtle crunch. Traditional processing methods include eating the raw pulp and seeds, boiling fruits into a thick dark syrup, sun-drying pulp into leathery slabs or cakes, and grinding or pounding seeds into a paste or meal for porridges and bread-like products. Fruits that split open on the plant or ground can be sun-dried to concentrate sugars, though prompt processing and good hygiene are important. Fermented juice or diluted syrup can yield mildly alcoholic beverages used in culturally specific rituals. Fruits are ripe from late June through July, when the outer skin splits longitudinally at the apex to expose the red interior. In Arizona, saguaro is protected by state law; harvesting fruits, ribs, or any part of the plant without appropriate permits or landowner permission is illegal. Many traditional harvest sites and practices are also embedded in Indigenous cultural and ceremonial contexts, and respect for local laws, land ownership, and Indigenous rights is essential.

Traditional Uses

The fruits are processed (i.e. dried, fermented, canned) and stored for year-round use. Seeds, rich in fat, are ground for use as flour and in porridges. The seed can be turned into a paste. The fruit can be used for syrup or made into conserve. The fruit are eaten. The red pulp of the fruit can be eaten fresh. The seeds are ground into flour and used in soups, sweetmeats and as a buttery paste on tortillas. The seed also produce an edible oil.

Medicinal Uses

None Known

Distribution

A subtropical plant. Mature plants will tolerate temperatures down to -7°C. It needs temperatures from 5-30°C. Seedlings need protection from cold. They can tolerate intense heat and sun. They must have acid soil. It suits hardiness zones 9-11. Hobart Botanical Gardens.

Where It Grows

Asia, Australia, Central America, Indonesia, Mexico*, North America, SE Asia, Tasmania, USA*,

Cultivation

It is grown only from seed. The seedlings have few branches and many spines. It can also be grown from cuttings.

Propagation

Saguaros are propagated almost entirely by seed, as they rarely produce vegetative offsets. Seeds germinate best on moist but well-drained mineral or sandy soil, often under partial shade from rocks or nurse shrubs. Natural recruitment is sporadic and closely tied to rainfall patterns and nurse-plant availability. In nursery conditions, sow seeds in shallow trays with sterile cactus mix, kept warm, lightly moist, and partially shaded until seedlings are established.

Other Uses

For the Tohono O'odham and other Sonoran Desert peoples, saguaro fruit harvest marked the beginning of the new year — a pivotal seasonal event combining subsistence and ceremony, embedded in stories, songs, and rules of conduct governing respect for the cactus and the land. Dried saguaro ribs were used for construction and tools, including the long poles used to knock fruit from the crown. Ecologically, saguaro is a keystone species of the Sonoran Desert. Cavities excavated by Gila woodpeckers and gilded flickers provide nesting sites for many bird species. Flowers are pollinated primarily by nocturnal nectar-feeding bats — notably the lesser long-nosed bat and Mexican long-tongued bat — and by diurnal visitors including white-winged doves, other birds, bees, and insects as blooms remain open into the morning. Fruits and seeds are dispersed by birds, mammals, and gravity.

Production

It is slow growing. It grows at 20 cm per year. It may only flower after reaching 3.5 m high. The fruit fall naturally and are dried by the sun and collected. They can be stored. The fruit ripen in one month.

Other Information

Saguaro fruits were a major food staple of the Papago and Pima Indians;

Notes

There is only one Carnegiea species. (It is often shown as scenery in movies.)

Synonyms

Also Known As

Kaktus karnegi, Pitayas, Sage-of-the-desert, Sahuaro

References (38)

• Andersohn, G., 1983, Cacti and Succulents. EP Publishing. p 68
• Anderson, E.F., 2001, The Cactus Family, Timber Press. p 49, 138
• Anderson, M., 2002, The World Encyclopedia of Cacti and Succulents. Hermes House, New York. p 55.
• Beckstrom-Sternberg, Stephen M., and James A. Duke. "The Foodplant Database." http://probe.nalusda.gov:8300/cgi-bin/browse/foodplantdb.(ACEDB version 4.0 - data version July 1994)
• Benson, L., 1969, The Native Cacti of California. Stanford University Press. p 173 (As Cereus giganteus)

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