Photographers capturing earlier than expected blooming of the iconic Joshua trees in the Mojave Desert are being asked to share their images with environmental biologists at Cal State Northridge University. The university team wants to determine the cause of the surprise display and what it means for the trees’ future.
They are asking the public to share pictures by uploading them onto the smartphone app iNaturalist to be used later to tell the story of this year’s “bonus bloom.”
“An individual observation may (not seem) very useful, but if you aggregate that over hundreds of people using the app and traveling all over the desert, that’s how I know that there are Joshua trees flowering as far east as Las Vegas right now,” said Jeremy Yoder, an associate professor of biology at CSUN. “It’s like this big crowd source surveillance network. It’s not a lot of effort for any one person to contribute, but add it together and it’s really, really powerful.”
Joshua trees, primarily found in the Mojave Desert, play an essential part of its ecosystem and are native to the vast swath of land while flourishing in colder winters and occasional snow.
Their natural blooming season begins late February through April after being pollinated by the yucca moth. This small insect plays a crucial role by collecting pollen and laying eggs inside the flower.
During the torrential raining season that hit the area this past fall through late December 2025, trees started blooming as early as November, which hasn’t been seen since 2018.
“(That year) we had a very cool summer and then a weird late rainfall, and so the thinking is that the trees figured conditions were right so they went for it and I think that’s probably what’s happened again this time,” Yoder said. “We had a couple of really big water weather systems come through in November and then again in December.”
Not all of the trees have already bloomed, leaving other blooms yet to come making for a longer period for visitors to enjoy nature’s splendor.
Since Joshua trees only have one pollinator, the yucca moth, the question Cal State Northridge’s biology team has been pondering is whether early blooming knocks them out of sync with their pollinators.
Pollinating is a complicated process, however, when adult yucca moths finish laying their eggs, they burrow into the ground and hibernate which could be for numerous years until the next time they expect trees to flower.
“When the moths … wake up, they come out of their cocoons … but we don’t know precisely what it is that makes them wake up,” Yoder said, adding they often perceive winter’s colder temperatures and know it has passed from one year to the next. “But it’s very possible all of these early flowers are just going to finish their life cycle and not get pollinated and if that’s the case it reinforces our sense that the moths are not maybe keeping up with the trees as closely as they need to.”
That speculation could be a grave threat not only to the trees but to the moths’ future reproductive populations.
Kirsten Zornado, a Cal State Northridge master’s student in biology on Yoder’s team, is studying the trees’ flowering and fruiting under weather conditions.
She is especially interested in mutualism or species interactions.
“The Joshua tree basically houses the moths and they grow up in the flowers and … the Joshua tree gets pollinated,” Zornado said. “That kind of relationship … is really sensitive to external changes (such as) temperature changes. I’m really interested in how those types of changes impact mutualism.”
When the public upload images on their smartphone, the time and place is displayed giving researchers the exact information necessary to document their findings.
Zornado said taking photos could be seen as an act of conservatism, an opportunity to not only commune with nature but be a part of a greater effort.
“When people can go out and repeat observations of the same tree … we can really see it from … before the flower even forms to the bud just starting to come out … the flowers forming to the fruits starting to kind of dissipate and fall off means that they’ve done a good job,” she said. “It’s the end of the life cycle (which) we love to see.”
A Joshua tree is extremely slow growing. Consequently, daily photos are not necessary. Taking a photo once a month will do the trick. And the best part is it doesn’t take fancy equipment.
“I’m planning on using this data in the next two years but there may be a grad student in five years who says ‘Oh there’s a great ton of Joshua tree data from 2020 (and beyond),” Zornado said. “That’s awesome, let’s use that, let’s ask another question.”
For more information about the college’s project, visit https://lab.jbyoder.org/. There you will also find instructions to download photographs onto the iNaturalist app.