Counting Flowers to read the Saguaro’s Future

Saguaros are more than just icons of the Sonoran Desert — they’re storytellers of the landscape. Their towering presence, delicate blooms, and ancient role in cultural traditions reveal the health of the desert we call home. But as extreme heat and unpredictable weather events become more common, saguaros are showing signs of stress.

To better understand what these changes mean, our very own Theresa Foley joined researchers and community leaders to look closer at saguaro flowers — fleeting blossoms that carry big clues about the cactus’s future. She recently coauthored research with Don Swann, a longtime biologist with Saguaro National Park, and shared her findings at the 2nd International Virtual Cactaceae Symposium.

Theresa’s presentation, “Temperature Change Variation in Biotic Communities of the Southwestern US and Northern Mexico, 1950–2020,” showed how 70 years of weather data reveal worrying warming trends. These changes directly affect the saguaros’ ability to bloom, reproduce, and survive long-term.

In the interview, Theresa explained how flower monitoring is unlocking new ways to track the cactus’s resilience:

“By observing the timing and number of flowers, we can begin to see how saguaros are responding to extreme heat, freezing events, and drought. Each bloom tells a story about survival — and about the future of our desert.”

This work isn’t just about science. It connects deeply with cultural traditions like the bahidaj harvest of the Tohono O’odham Nation, where saguaro fruit is gathered each summer to create syrup, jam, and even wine. The survival of these practices depends on the cactus’s ability to thrive in a changing climate.

From documenting superblooms to puzzling over off-season flowering, Theresa and her colleagues are piecing together the mysteries of this desert giant. Their findings will help guide conservation efforts and inspire future generations to protect the saguaro — the beating heart of the Sonoran Desert.