Joshua Trees Bloom Early, Scientists Need Your Photos

Desert dwellers across the Southwest are spotting something unusual this winter: Joshua trees covered in white flowers that shouldn't appear until late February.

Scientists are turning to citizen photographers to understand why these iconic desert plants are blooming three months early. They're asking anyone who spots flowering Joshua trees to snap photos and upload them to iNaturalist, a platform where everyday nature watchers help researchers track wildlife patterns.

The early bloom might sound harmless, but it could threaten the survival of both the Joshua tree and its only pollinator, the yucca moth. These rice-sized insects and the spiky desert plants depend entirely on each other in one of nature's most delicate partnerships.

Here's how it normally works: Joshua trees bloom in late February, just as yucca moths emerge from underground cocoons where they've spent the winter. The moths pollinate the flowers while laying eggs inside them, and their caterpillars later munch on some of the seeds before burrowing back into the soil to wait for next year's bloom.

But this year's early flowers appeared in October and November, when moths are still safely tucked underground. Jeremy Yoder, a biologist at California State University, Northridge, fears the moths won't emerge because it's still too cold.

Without moths to pollinate them, the trees won't produce fruit or seeds. That's a serious problem for plants that already face tough odds: most Joshua tree seeds get eaten by desert animals, and only a handful survive the 40-plus years it takes to mature.

Something similar happened in fall 2018, but those early blooms stayed mostly in the southern Mojave Desert. This time, trees are flowering early throughout their entire range across California, Nevada, Arizona and Utah.

The Bright Side

Your photos could crack the case. Scientists suspect intense late-season rains triggered the unusual bloom, but they need observations from across the desert to spot patterns. The data from citizen scientists will help researchers understand which areas received the most rain and whether those early flowers eventually produce fruit.

The citizen science approach means anyone with a smartphone becomes part of the solution. Researchers are especially hoping people will photograph the same trees multiple times throughout the season, creating a timeline of what happens next.

Even if this year's bloom doesn't produce seeds, understanding what triggered it will help protect these slow-growing desert icons for future generations.