Common Name: Saguaro

General Information

Carnegiea gigantea is a very spiny, evergreen, succulent columnar cactus with usually 1 - 10 upright branches (exceptionally, up to 50 branches); it can grow up to 16 metres tall with the stem 25 - 75cm in diameter. Very slow-growing, the plant first develops as a single column, the branches only appearing after around 50 - 70 years when the plant is 4 metres or more tall[, ].
The plant is harvested from the wild for local use as a food, medicine and source of materials. The fruits are a staple food of the native people and are harvested in large quantities, many being preserved for later use. The plant is much grown as an ornamental.
Carnegiea gigantea has a wide range. Even though there is a decrease in the population, this species is still locally abundant and the observed decrease is not sufficient to trigger a threat listing[]. Although not considered endangered, the plant is protected under the Arizona Native Plant Law. The most significant impact on their populations is posed by urban development, and developers have a duty to move or protect any plants that would otherwise be destroyed during building operations[]. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

,

Range

Southwestern N. America - California, Arizona, northern Mexico (Sonora)

Habitat

Desert scrub and thorn scrub, growing on well-drained land, on hillsides and on plains; at elevations from sea level to 1,370 metres[]

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	10.00 m
Growth Rate	Slow
Pollinators	Bats, Bees, Birds
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Carnegiea gigantea is native to the semi-arid and arid regions of southwest N. America, where rainfall occurrs in winter and again in the summer. Amounts can vary widely from year to year but average annual amounts are around 150 - 400mm. The plant is not very cold tolerant but can survive short periods with temperatures falling as low as -5°c so long as the soil is free-draining and the weather is dry. Death will occur if the plant is exposed to below freezing temperatures for 29 or more consecutive hours[]. The plant requires hot summers and mild winters if it is to thrve.
Requires a sunny position. The plant is found in the wild on shallow soils that are light, coarse-textured, and
rocky[]. Carnegiea gigantea does not occur at sites where soils are saline or subjected to flooding or long periods of freezing[].
An extremely slow-growing plant, reaching only 6mm tall after two years. It only starts flowering once it has reached about 30 - 35 years of age and a height of about 2 metres[]. The first branches, which grow out from the sides of the stem, only appear after it has reached a height of 4 - 5 metres and an age of 50 - 70 years.
The plant has a deep anchoring taproot up to 1 metre long and an extensive, shallow, lateral root system that allows it to take up water quickly after the infrequent rains typical of the Sonoran Desert. During this time the trunks swell considerably[10.50].
The plant is the state flower of Arizona[].

Edible Uses

Fruit - raw or cooked. The delicious fruits have a sweet, juicy, red flesh with lots of tiny, black, nutty-tasting seeds (up to 2,000 per fruit)[]. They can be eaten fresh or turned into juice, syrup, jam, wine or vinegar[, ]. They are also dried and stored for later use[]. When dried as fruit leather, it can be kept for many months and is eaten as a nutritious trail food[]. The red, fleshy fruits are 45 - 95mm long and 25 - 44mm in diameter[].

The seeds are rich in protein and oil. They can ber ground into a flour and made nto a mush or used to prepare a cake[, , ]. The seeds can also be made into a buttery paste that is used on tortillas[].

An edible oil is obtained from the seed[].

The succulent stems have been used in times of need as an emergency supply of water. This is said to at least be refreshing, though unpleasant and slimy to the taste[].

Medicinal

The woody skeleton of the plant can be used as splints for broken bones[].

A gruel was traditionally made from the saguaro fruits and used as a medicine to make a mother's milk flow after childbirth[].

Other Uses

Some birds dig their nests into the plant's flesh; as a response the plant produces a hard callus lining to the cavity that seals it off from the surrounding living tissue. Once the plant has died and the soft flesh has rotted away, the hard lining of these old bird nesting cavities remains intact, forming curious looking container-like structures that stick out among the remains of the dead plant. These so-called 'saguaro boots' can be fashioned into various containers or vessels, including drinking bottles, dishes, and tobacco pouches[].

The internal 'woody ribs' (which form an inter-connected ring-like skeleton) of dead stems provided building materials (especially roof beams)[]. They are made into slats for house frames, walls, and shelves, and also fashioned into walking sticks, saguaro fruit-gathering poles, light tools, tongs for picking cholla buds and joints, cradleboards, fire drill boards etc[, ].
The wood is used as firewood[]

Propagation

Seed - it has a short viability and is best sown as soon as ripe. Fresh seed germinates readily[].