Carnegiea gigantea, commonly known as Saguaro, is a very slow-growing cactus that may add only 1 to 1,5 inches (2.5 to 3.8 cm) in the first eight years. Saguaro grows arms or lateral stems, but it may take up to 75 years to produce the first one. This cactus is long-lived. Many specimens found in the desert are 175 years old.
Saguaro has a barrel-shaped body with peripheral stems called arms. The exterior of the trunk is pleated due to the way it grows. The pleats expand, allowing the cactus to gather extra water in the rainy season and store it in its tissues. An adult cactus may weigh 6 tons or more when filled with water and requires a strong internal support skeleton of connected ribs. A young growing Saguaro may only be a few inches tall as ten-year-old plants and take decades to resemble adults.
This cactus is native to and only grows in the Sonoran Desert. Saguaro is not found in the entire desert but only in areas that do not freeze and at certain elevations. The freezing point is one of the most important considerations of where Saguaro grows. It is found from sea level up to 4,000 feet (1,220 m). If it is growing above 4,000 feet (1,220 m), it survives only on south slopes with fewer freezes of shorter duration. Saguaro is an important part of the desert ecology as a habitat and food.
Growing Conditions and General Care
It is not legal to procure a Saguaro for home cultivation by digging it out of the desert. Beyond that, a mature Saguaro almost always dies when transplanted.
Saguaro babies grow under the protection of nurse trees. They will continue to grow, and often their nurse tree will expire. It is thought that the Saguaro may cause the nurse tree to die by competing for resources. The nurse trees shelter Saguaro babies from the sun's harsh rays and disperse moisture from evaporation.
Saguaro needs to grow in well-drained grit and receive low water levels, with the soil drying completely between watering. Annual fertilizing with cactus food in spring will help the plant complete its growth cycle.
Common cactus pests, such as scale and mealybugs, will require manual or chemical controls.
Saguaro Cactus Blossoms
Saguaro is slow to develop and can be 35 years of age or more before producing the first flower. The flowers are creamy-white, about 3 inches (7.5 cm) in diameter, and appear from May until June. They only open at night and close during the day, which means they are pollinated by moths, bats, and other nocturnal creatures. The flowers are generally located at the end of the arms but may occasionally decorate the cactus' sides. They are the state flower of Arizona.
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