11 Things You Didn’t Know About Saguaro Cacti

Science Friday’s broadcast in Phoenix, Arizona, got us thinking more about a popular desert fixture—the saguaro cactus, a huge plant with a big appetite for water. Did you know that…

1. Saguaros are the largest cactus species in the U.S.—they can grow more than 40 feet tall. (The largest species in North America is the giant cardon cactus, which grows in parts of Mexico.)

2. A typical saguaro can live between 100-200 years. (That said, “We are not entirely sure of the true age of some of the largest individuals,” says Kevin Hultine, a plant physiologist at Phoenix’s Desert Botanical Garden.)

3. A fully-grown saguaro can weigh more than a ton.

4. Depending on how much water they amass, saguaros can shrink or swell in girth by 20-25 percent over the course of a year, according to Hultine.

5. Saguaros have an intricate root system. A single “taproot” grows straight down about five feet to access water that’s stored deep underground. A saguaro’s main roots, however, extend like a maze about three inches under the surface to easily collect rainwater.

6. 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,” says Hultine.

7. The saguaro’s bloom is Arizona’s state flower.

8. The saguaro was given its scientific name, Carnegiea gigantic, in honor of industrialist Andrew Carnegie, whose Carnegie Institution established the Desert Botanical Laboratory in Tucson, Arizona, in 1903.

9. Saguaros don’t always assume the familiar, forked silhouette of cowboy lore—a small number appear “crested” by a fan-like structure referred to as a cristate. But these “are very rare,” notes Hultine.

10. Saguaros are culturally important to the Tohono O’odham Nation. These Native Americans harvest ripe saguaro fruit in the spring to make wines, jams, and jellies. Saguaro wine is ritually consumed during Nawait I’i, a Tohono O’odham rain ceremony.

11. Saguaros—which make for expensive lawn adornments—have become black market commodities, with poachers raking in a few thousand dollars for their hauls. “This has been one of the major traditional threats to saguaro,” according to Hultine.