The largest cactus in North America is no stranger to harsh conditions. Native to the Sonoran Desert, the saguaro cactus has evolved to endure little rainfall and summer temperatures that routinely soar above 100°F. But in our warming world, even the “monarch of the desert” is struggling to cope with extreme heat and extended periods of drought. Climate change, together with habitat loss, intensifying wildfires, and the spread of non-native species, is threatening the welfare of this iconic plant with profound connections to desert wildlife and human history.

The saguaro, also known as “the giant cactus,” occurs naturally and only in southern Arizona, southeastern California, and northwestern Mexico. The plant is slow to develop, rarely exceeding a few inches of growth in the first ten years of its life. Seedlings face low survival rates as they brave temperature extremes, browsing animals, and wind-blown debris. Saguaros often grow alongside “nurse trees,” such as mesquites and ironwoods, that protect them from summer sun and winter frosts. Those that live to thirty-five years of age start producing white, funnel-shaped flowers that mature into vibrant red, fleshy fruits. After about sixty years of growth, the cacti develop from single columns into their famous branched silhouettes.

It takes more than a century for a saguaro to reach adulthood, when it stretches upwards of forty feet tall. Strong, thick spines shade the plant from sunlight, ward off drying winds, and deter destructive animals. Shallow roots radiate up to fifty feet from the main stem, anchoring the cactus and absorbing rainwater. The succulent can expand its pleated body like an accordion to store over 1,000 gallons of water and withstand months without rain. These adaptations enhance the plant’s longevity and intrigue. The average lifespan of a saguaro is 150 to 175 years, and some may live to be over 200. In a 1912 account of his travels through the Sonoran Desert, Norwegian explorer and ethnographer Carl Lumholtz deemed the species “by far the most noteworthy representative of plant life in the desert, being, in fact, one of the most remarkable plants on the globe.”

Many of the birds, mammals, and insects that inhabit the Sonoran Desert rely on the saguaro for shelter, food, and nesting sites. Gilded flickers and Gila woodpeckers, for instance, circumvent the plant’s sharp spines to excavate nest cavities inside its pulpy flesh. When the housebuilders abandon a cavity, other birds move in, relishing a refuge that can be almost 20°F cooler than outside temperatures in summer and vice versa in winter.

From late April through early June, pollinators delight in the creamy white flowers that spring from the saguaro’s trunk and arms. In midsummer, desert wildlife feast on the plant’s ripening fruit. According to biogeographer Taly Dawn Drezner, saguaro flowers and fruits are made even more valuable by the timing of their appearance, offering moisture and nutrition during the hottest and driest stretch of the year.

Desert critters aren’t the only beings that derive sustenance from the saguaro. The Tohono O’odham Nation have forged a deep relationship with the plant, which they call ha:sañ, over thousands of years. Their annual harvest of saguaro fruit is a sacred ritual that marks the start of the new year in the O’odham calendar. In June or July, gatherers wield a kuipad—a long pole made from a saguaro rib—to free the ovular fruits from the cactus stem. The pulp is processed into a thick, sweet syrup used to make ceremonial wines that accompany dayslong prayers for monsoon rains. The fruits are also eaten fresh, cooked into jams and jellies, or sun-dried for long-term preservation.

“The laborious, weekslong harvest process also reinforces crucial connections to the Creator, the natural environment and fellow O’odham across generations,” writes Giovanna Dell’Orto on the ritual, which is experiencing a resurgence as the Tohono O’odham seek to protect their traditional way of life.

In addition to consuming saguaro fruit, the O’odham have used the cactus body for construction. The woody ribs are comparable to other hardwoods, ideal for building fences, ramadas, and homes. These ribs are incredibly versatile, further employed to splint broken bones, fashion equipment for traditional stick games, and craft lances and arrows. But for the O’odham people, the saguaro is more than a provider of nourishment, tools, and shelter. The plant is family.

“Ha:sañ to us are like people, and we respect them that way,” explains Silas Garcia, a member of the O’odham community, in an interview with Dell’Orto. Garcia learned to harvest the cherished fruit as a child with his aunt on the O’odham reservation.

For others, the saguaro is an acclaimed emblem of the American Southwest. The plant’s silhouette adorns Arizona license plates, and its pale bloom is the state flower. The cactus has long enchanted artists, from photographers who capture the plant’s towering form to filmmakers who frame the species in desert backdrops. Multiple poets have contemplated the significance of the saguaro; Harriet Monroe, for example, portrayed the cactus as a wise and enduring witness to the passage of time. Her 1914 poem, “The Giant Cactus of Arizona,” begins:

The cactus in the desert stands
Like time’s inviolate sentinel,
Watching the sun-washed waste of sands
Lest they their ancient secrets tell.
And the lost lore of mournful lands
It knows alone and guards too well.

This reverence for the desert giant contributed to Herbert Hoover’s decision to secure 66,000 acres of saguaro habitat through the establishment of Saguaro National Monument in 1933. John F. Kennedy later added 15,000 acres of cactus lands to this reserve, which was designated as Saguaro National Park in 1994. The national park is home to the largest concentration of saguaros in the country, supporting approximately two million individual plants.

Despite protection under state and federal laws, the saguaro cactus continues to suffer vandalism and habitat loss. In recent years, the construction of a wall along the United States-Mexico border under President Donald Trump toppled untold numbers of saguaro cacti.

“They just bulldozed all the way through,” Lorraine Eiler, a Hia-Ced O’odham woman and former member of the Tohono O’odham council, told journalist Boyce Upholt. “It’s like they just completely overran your home, your beliefs, things that matter to you as a person, as a family, as generations of family,” she added.

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The incident inspired movements to protect the saguaro and other culturally significant plants from additional harm, such as the Sacred Plant Biocultural Recovery Initiative. Led by ethnobotanist and author Gary Paul Nabhan, this multicultural, interfaith, intertribal effort is working with the National Park Service, the Tohono O’odham Nation, and the Hia-Ced O’odham Alliance to return saguaros to the damaged borderlands.

“The goal is to have them in their original sacred places under the care of their original caretakers,” Nabhan explains in an interview with agricultural expert Arty Mangan.

The saguaro is further threatened by urban development, invasive grasses that increase wildfire risk, and climate change. A recent study reports a direct link between the diminished health of giant cactus species and extreme weather. Researchers found that after anomalous heat and drought events in 2020, the condition of saguaros at the Desert Botanical Garden in Phoenix, Arizona, declined significantly, driven primarily by limited water resources. Annual saguaro death rates at the garden jumped from 2 to 7 percent between 2020 and 2023. While the plant’s shallow root system is advantageous for soaking up rainwater that would otherwise evaporate before permeating the soil, when there’s no rain, it struggles to access moisture deep underground. According to the same study, “long-lived succulent plant species are suffering extreme stress that is causing increased mortality that has the potential to restructure communities throughout the Sonoran Desert.”

The giant cactus is exceptionally resilient and long-lived—but not invincible. The plant is one of countless species grappling with local and global threats. Although saguaros are not at risk of extinction, their populations are declining, and when a mature cactus dies, it takes more than a century to replace it. We must afford the species the same respect and protection upheld by the O’odham people and stewards of the Sonoran Desert. Shifts in saguaro populations will ripple throughout the plant’s extensive network of connections to other elements of the desert landscape, and to us. The Dumbarton Oaks Plant Humanities Initiative seeks to highlight these relationships and the inextricable nature of plants and human life.

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