The Saguaro cactus of the Sonoran Desert (Carnegiea gigantea) is one of the defining plants of the American Southwest. These plants are large, tree-like columnar cacti that develop branches (or arms) as they age, although some never grow arms. These arms generally bend upward and can number over 25. Saguaro cactus are covered with protective spines, white flowers in the late spring, and red fruit in summer. Saguaros are found exclusively in the Sonoran Desert. The most important factors for growth are water and temperature. If the elevation is too high, the cold weather and frost can kill the saguaro. Although the the Sonoran Desert experiences both winter and summer rains, it is thought that the Saguaro obtains most of its moisture during the summer rainy season. You find this cactus in southern Arizona and western Sonora, Mexico. At the northern portion of their range they are more plentiful on the warmer south facing slopes. A few stray plants can also be found in southeast California. The saguaro is not currently listed as threatened or endangered. Arizona has strict regulations about the harvesting, collection or destruction of this species. With the right growing conditions, it is estimated that saguaros can live to be as much as 150-200 years old. Saguaro are very slow growing cactus. A 10 year old plant might only be 1.5 inches tall. Saguaro can grow to be between 40-60 feet tall (12-18m). When rain is plentiful and the saguaro is fully hydrated it can weigh between 3200-4800 pounds.
The saguaro cactus has been described as the monarch of the Sonoran Desert, as a prickly horror, as the supreme symbol of the American Southwest, and as a plant with personality. It is renowned for the variety of odd, all-too-human shapes it assumes, shapes that inspire wild and fanciful imaginings
Despite the spines, which prevent hungry animals from feasting on their tissues, saguaros serve as “hotels” for birds such as Gila woodpeckers, which carve out nest holes in the plants. These birds typically wait several months before moving in to give the pulp of the cactus time to dry and create a solid casing around the cavity. “Sagauros are characterized as foundation species because they support so many other species in the ecosystem,”
The Saguaro Cactus of the Sonoran Desert is a hallmark of the American Southwest
- The saguaro is the largest cactus in the United States.
- Most of the saguaros roots are only 4-6 inches deep and radiate out as far from the plant as it is tall. There is one deep root, or tap root that extends down into the ground more than 2 feet.
- After the saguaro dies its woody ribs can be used to build roofs, fences, and parts of furniture. The holes that birds nested in or “saguaro boots” can be found among the dead saguaros. Native Americans used these as water containers long before the canteen was available.