Ask a roomful of kids to draw a desert and odds are good that most of their drawings will include a saguaro cactus, waving two friendly (albeit prickly) arms.
Despite the endearing ubiquity of that image, it’s not a sight you’ll actually see in most of the planet’s 71 deserts. In fact, the only home to the tree-like saguaro (Carnegiea gigantea) is the Sonoran Desert, which stretches across southeast California, the southern half of Arizona, and the northwest states of Mexico.
“Saguaros are such an icon of this area, of the Southwest in general,” says Beth Hudick, interpretation, education, and outreach manager at Saguaro National Park in southern Arizona. “If you close your eyes and picture a cactus, it’s a saguaro.”
The Sonoran Desert is no stranger to heat, but as climate change makes heatwaves more frequent, intense, and long-lasting, the resilience of this desert’s most beloved plant is being tested.
Tucson is the cactus’s stronghold, bookended by Saguaro National Park on both its east and west edges, but a 2018 study by the National Park Service rated the park as one of those put at greatest risk by climate change. The city, meanwhile, smashed heat records this past summer, including the longest number of consecutive days in the triple digits.
Even plants native to this desert feel the heat: In the past few years many saguaros have lost arms, toppled over, or burned.
Although it’s unlikely these iconic cacti are headed for extinction anytime soon, they’re in decline. And these newly harsh conditions have people wondering what the species’ survival will look like.
From Baby Boom to Bust
Let’s start with the good news: Saguaros are not endangered. Not in the short term, at least. They can live 200 years, and they had a baby boom in the 1980s, according to Hudick, so the current population of saguaros in the park is “quite healthy.”
Saguaros’ most famous characteristics help protect them. Pleats in their trunk and arms allow them to grow pleasantly plump after heavy rains. Columns of spines shade them and shield them.
But it takes time to build up those defenses.
Hence, the bad news: Establishment of new saguaros has nearly ceased. A study published by the National Park Service in 2018 found that since the early 1990s, the number of young saguaros in this and two other parks in the region has been disturbingly low — mainly due to a decline in precipitation coupled with higher temperatures.
The Sonoran Desert has two rainy seasons — in the winter, when the gentle rains come, and in the late summer when the dramatic monsoons arrive. Arizona has been in a long-term drought since 1994, so it’s seen less of both. Without sufficient moisture a seed might still germinate, but not be able to establish itself.
The young saguaros that do pop up face a tough beginning. Seedlings grow very slowly at first — only an inch or so annually during their first handful of years. It may be 70 years before they sprout arms and 150 before they reach their full height of 40-50 feet, with some rising higher.
“They’re so vulnerable when they’re little,” Hudick says, “because they can’t absorb a lot of water. That’s why it takes them so many years to get to the size that you can actually see and notice. [Park] visitors will not notice saguaros that are less than ten years old.”
People still look for them, though. The Park Service and hundreds of citizen scientists and saguaro enthusiasts conduct a census every decade to monitor the health of the plants over time.
The results of the most recent survey, published in that 2018 study, showcased just how few new saguaros are surviving. Of the nearly 10,000 saguaros surveyed, teams located just 70 young plants under 4 inches tall or less than 11–15 years old.
“It’s not a die-off,” Hudick reiterates. “It’s a reduction in recruitment. That is the concerning thing.”
Invasives and Fire
A drought-stressed landscape is also more susceptible to invasive species. The archenemy of the Sonoran Desert is buffelgrass (Cenchrus ciliaris), which covers the ground and crowds out places where saguaro seedlings and other native plants would start life.
Buffelgrass also introduces another threat: fire.
Native to much of Africa and southern Asia, buffelgrass grows in savanna grasslands with sparse trees, where it adapted to survive frequent fires.
The Sonoran Desert’s flora evolved for heat, not flame. Historically, natural fires only burned here once every 250 years, and when they did, they didn’t get far. That changed with buffelgrass, which turns flammable as it dries out, producing twice the fuel of native vegetation.
“This is not a fire-dependent ecosystem,” Hudick says. “The desert isn’t meant to have widespread fires like prairies or forests. And when we have those fires that are carried by buffelgrass, then we see the death of the large saguaros.”
Introduced to the Southwest in the 1930s, buffelgrass has spread most swiftly in the past quarter-century. By 2010 buffelgrass infestations were expanding roughly 35% per year. Now, thanks to thick invasions of grass, fires here burn hotter, faster, and over larger areas.
Besides saguaros, these fires also kill other iconic but slow-moving species, including desert tortoises and Gila monsters.
And thanks to climate change, the fire season has also grown longer.
Unlike excess heat and meager rain — factors hard to control — buffelgrass can at least be managed, Hudick says. Staff and dedicated volunteers go out each year to pull buffelgrass during a narrow window of time before it sets seed.
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Meanwhile, a new and dangerous invasive has arrived on the scene. The cheerful yellow ball-shaped blooms of stinknet (Oncosiphon pilulifer) produce thousands of seeds and can quickly smother a landscape and outcompete native wildflowers. It, too, is highly flammable.
Cactus Dominoes
When Hudick and I spoke outside the East Park’s visitor center, it was a lovely 70-degree day in December under a cloudless blue sky — no rain coming anytime soon. (Indeed, December 2024 turned out to be Tucson’s driest and warmest December on record.)
Here the Rincon Mountains rise to our east. On every side of the city, it’s these unfurling foothills that saguaros seem to love best. Some stands are so dense they’re called cactus forests.
“Saguaros really are a keystone species in this ecosystem, culturally and ecologically,” Hudick says. “A lot of animals rely on the saguaro.”
Animals such as doves, bats, javelina, and foxes depend on saguaros for their fruit, while pack rats and jackrabbits eat their moist flesh. Gila woodpeckers and gilded flickers make nest holes in the trunks and large arms. Other birds occupy abandoned holes or build nests in the crook of a raised arm, while raptors perch on tall saguaros to spot prey.
“If the saguaro were to disappear from the landscape, I think we would see largescale change ecologically — it’d change the way the whole desert community looked,” Hudick says. “People are not necessarily going to see that in their lifetime, because the changes are happening slowly. It might be 50 or 60 years before we see those larger saguaros die off and nothing coming in to replace them.”
The Saguaro Way of Life
An hour west, another group is keeping a watchful eye on the saguaro. The Tohono O’odham, or Desert People, have lived in southern Arizona for more than 5,000 years. The saguaro appears in one of their creation stories — their name for the cacti is haha:sañ (pronounced “ha-ha-shawn”).
“The saguaro is an ancestor to us,” explains Jacelle Ramon-Sauberan, a member of the Tohono O’odham Nation, an instructor of language and culture at Tohono O’odham Community College, and as of 2024, the first Tohono O’odham board member of Friends of Saguaro National Park. “In the stories that we tell in the winter months, the story of how the saguaro came to be is a story that is told every year.”
In the creation story, a mother is obsessed with playing toka, a traditional field hockey game, and often neglects her young son. One day the child is so hungry and lonely that he goes in search of her, only to be laughed at by others and sent back home by his mother. In despair he sinks into ground, weeping, and rises later as a saguaro, a plant that has fed Ramon-Sauberan’s people “since time immemorial,” she says.
The tops of mature saguaros produce white blooms in late spring, pollinated in daylight by birds and bees, at night by bats and moths that all feed on the nectar. In summer those blooms produce red, juicy fruit. Using a pole fashioned from long saguaro ribs, her people harvest the fruit and turn the bright red pulp into jelly, syrup, and ceremonial wine.
But while the fruit provides nourishment and medicine, climate change has made the time of harvest less reliable.
“I know there have been saguaros that have produced and bloomed out of season,” she says. “It’s hot one day, it’s cold another, what’s going on? We don’t have a word for climate change.”
Ramon-Sauberan teaches a Tohono O’odham food systems class in which she starts out with the basics: What is climate change? What are we seeing now? What did we see in the past?
Her community on the reservation is discussing the same issue.
“We’re all trying to figure this out as we go, whether you are a human being or a plant. We’ve gotta take a step back and realize everything on this earth has a spirit, going back to our traditional ways. What did we used to do? We used to sing to our crops and harvest, and we do have songs for the harvest.”
In recognition of this rich cultural history, Saguaro National Park recently hired Raeshaun Ramon as its first permanent Tohono O’odham ranger since the park was created.
“He’s incorporating our culture and our language in what he does, which is really cool,” Ramon-Sauberan reports. “Singing is really important in our culture, and healing, and I really like that he’s started to bring that back. Our lands need to be sung to, our words need to be shared, and singing is one of the ways that we do that.”
She hopes that a mix of those traditions with contemporary science will achieve a middle ground that helps cope with climate change.
In speaking of the Tohono O’odham legend of the saguaro, Ramon-Sauberan says “there are lessons to be learned, consequences to our actions.” That was true in the death of the boy, and it’s true today. In the saguaro legend, it’s Crow who tells the people the sad truth that they didn’t care for the boy as they should have or realize his importance — not until he’d disappeared.
Will we learn that lesson in time to protect saguaros?
“I worry, but at the same time we’re resilient people, we’re desert people. We’ve survived and learned to adapt. I feel like our haha:sañ will, too.”
Seeds of Hope
As bad as things are for saguaros, Hudick says their cultural importance could be their greatest strength.
“I do think the people in this area love their saguaros, they love their desert, they feel very passionate about protecting it,” she says. “I think focusing on the positive actions we can take, the ways that we as individuals can help mitigate the impacts of climate change, helps to put it into a context where it’s not so hopeless.”
She pauses and looks out at the saguaro’s stronghold, then adds, “I think we all need hope.”
