Nathan St. Andre holds perhaps the most extensive photographic portfolio of southwestern Utah’s Joshua trees in the country. Since 2021, he has captured the full lifespan of these spindly desert dwellers at Beaver Dam Wash – from fledgling stalks to aging giants. His images frame them beneath the Milky Way, lightning bolts, full moons, comets – even the aurora borealis and rare super blooms. He’s seen them dusted in snow and bathed in double rainbows.

But beyond the striking visuals, St. Andre’s work seeks to unveil a deeper mystery: how little we actually know about this desert icon.

Despite their nickname, Joshua trees (Yucca brevifolia) aren’t trees at all – they’re members of the Asparagaceae family, which includes agaves and hostas. Their thick, twisted trunks and shaggy crowns of spiky leaves could’ve leapt from the pages of a Dr. Seuss book. They anchor themselves up to three feet into the soil to endure Utah’s intense desert climate.

According to legend, settlers of The Church of Jesus Christ of Latter-day Saints in the 1800s named them after the biblical figure Joshua, whose arms stretched skyward in prayer and guidance.

These remarkable plants have inhabited the Southwest for more than 2 million years. Most live around 150 years, though some survive more than 300. Found only in the American Southwest, they thrive in the arid soils of mesas, plains and slopes between 2,000 and 6,000 feet. Utah is home to the species’ northernmost grove, tucked into the Joshua Tree Natural Area.

St. Andre first encountered this grove in 2016 while working as a wildlife technician for the State of Utah. A trip to California’s Joshua Tree National Park in 2020 brought him back to Utah’s cluster with new eyes. What he saw surprised him: Utah’s Joshua trees looked noticeably different – shorter, slimmer, with more upward-reaching branches. And no one seemed to know why.

Only recently, in 2013, did a study published in Molecular Ecology identify two separate varieties of the species. The western Joshua tree grows in California and Nevada; the eastern variety does too, also native to Utah and Arizona. A small patch in Nevada is the only place both overlap. Each relies on a specific yucca moth for pollination – one species of moth for each variety, with no overlap. These moths, no bigger than a grain of rice, are the sole pollinators of Joshua trees.

While this discovery shed some light, much remains unknown. As both a scientist and artist, St. Andre found himself captivated by the gaps in understanding – and determined to explore them through photography.

“The further I’ve dug into these plants, the more it’s become blatantly clear that their life, their history and their existence are a mystery,” he said.

He’s been methodically documenting the stages of a Joshua tree’s life: the straight, unbranched juveniles; the adults with outstretched limbs; and the weathered elders shaped by time and wind. His work isn’t just an artistic pursuit – it’s an informal archive, a visual catalog of a plant that has fascinated and puzzled scientists for decades.

One of the rarest sights he’s captured was a Joshua tree in bloom – an unpredictable and little-understood event. Some believe a cold snap is needed to trigger flowering, while others attribute it to a mix of rainfall, temperature and plant maturity. A persistent myth claims they bloom only once every hundred years, though there’s no scientific evidence to support that.

St. Andre was stunned by the size of the blossoms, calling the clusters “as big as a human head,” with soft, bulbous flowers and an oddly pungent scent. “Scientists just don’t know exactly what makes them bloom,” he said. “But if that 100-year idea has any truth to it, I witnessed something truly rare.”

Through his photography, St. Andre offers not only dazzling visuals but an invitation to wonder. “These plants, which are literally named after a prophet of God, are not always guaranteed to be here,” he said. “The Mojave Desert is defined by the presence of Joshua trees. That icon deserves to be seen.”