Joshua trees (Yucca brevifolia) are some of the most iconic figures of the southwestern deserts. While most often associated with California and Joshua Tree National Park, a tiny portion of their range extends into our corner of southwestern Utah. Not actually a tree but rather a tall gangling species of yucca, Joshua trees are frequent companions on low-elevation hikes in the St. George area, where the Mojave Desert makes its last stand before disappearing into the higher altitude mountains and valleys of the Colorado Plateau and the Great Basin.
Like many species of yucca, Joshua trees don’t flower every year, but instead only when temperature and rainfall conditions are favorable. We had yet to see a flowering Joshua tree in our three years in Utah, only the dry brown stalks of blooms gone by. This winter has been abnormally wet however, and in early March we started to notice large flower buds forming on a handful of Joshua trees (in the median of Interstate 15) that we drive past regularly. By the end of March, the bloom was in full swing! We decided to head into the Virgin River Gorge of extreme northwestern Arizona for a closer look.
Joshua trees produce truly massive flower stalks: 1-2″ feet long and densely packed with large, rubbery, cream to nearly yellow-colored petals. Perhaps even more impressive are the flower buds, which resemble gigantic green and purple artichokes in the days and weeks before the flowers emerge:
This year’s Joshua tree bloom wasn’t limited to Utah and Arizona. Throughout the Mojave Desert, Joshua trees have been flowering in large numbers, thanks to a series of wet and cold winter storms over the past few months. In fact, some Joshua trees in California were observed blooming as far back as last November. This fact may seem innocuous, but actually gives ecologists cause for concern given that Joshua trees are pollinated by just one insect: the yucca moth. Yucca moths are the sole species with the proper behavior and anatomy to pollinate the Joshua tree. Consequently, Joshua trees are 100% dependent on the yucca moth for reproduction and survival, while the larvae of the yucca moth are similarly dependent on the Joshua tree seeds for nutrition. For these symbiotic species to survive, the timing of the Joshua tree bloom must coincide with the life cycle of the moth. As climate change warms the southwestern deserts, there is concern that this could cease to be the case, as described in the linked article above. Joshua trees are a keystone species of the Mojave Desert, providing food and shelter for a host of other animals large and small. A decline in their populations would be devastating for the desert as a whole.
All of this is reason to work toward protecting our remaining stands of Joshua Trees, and a reminder to always be mindful and respectful when photographing sensitive species and landscapes. The “superblooms” of poppies and other wildflowers in the southwest over the past few months have highlighted the ecological damage that occurs when swarms of folks looking for their next Instagram photo descend en masse on delicate landscapes without regard for the environment.
Fortunately, many photographers are aware of the threat photography can pose to these beautiful environments and are working to combat the problem. I’m pleased to share that I have joined Nature First: The Alliance for Responsible Nature Photography. The goal of Nature First is to promote responsible nature photography through adherence to seven core principles:
Prioritize the well-being of nature over photography.
Educate yourself about the places you photograph.
Reflect on the possible impact of your actions.
Use discretion if sharing locations.
Know and follow rules and regulations.
Always follow Leave No Trace principles and strive to leave places better than you found them.
Actively promote and educate others about these principles
If you are a nature or landscape photographer, check them out and consider joining. Following these principles will ensure that spectacular events like Joshua tree blooms are still around for future generations of humans and yucca moths to enjoy!
Driving across the southwestern United States, one could be forgiven for thinking that all deserts are the same. However, differences in elevation, temperature, topography, and precipitation make them distinct in ways that are often hard to comprehend from a fast-moving car.
For all their differences though, both the subtle and the striking, the Mojave and Sonoran Deserts share one thing in common; the most visible symbol of each is a large, majestic, and photogenic plant perfectly suited for the harsh conditions in which it evolved to inhabit.
For the Mojave Desert, that plant is the Joshua tree (Yucca brevifolia). Not actually a tree but rather, as the scientific name betrays, a species of Yucca, early settlers bestowed the befuddling name upon this plant after noticing that the contorted arms resembled the prophet Joshua raising his arms to the sky in prayer.
Today, the Joshua tree is considered an indicator species for the Mojave Desert, as many other inhabitants of the Mojave (two-legged, four-legged, and winged alike) depend on it for survival. The Joshua tree grows through portions of western Arizona, southeastern California, and southern Nevada, but some of the largest and healthiest stands are protected within the boundaries of Joshua Tree National Park and Mojave National Preserve.
For the Sonoran Desert, the symbolic plant is the saguaro cactus (Carnegiea gigantea). Despite the nearly ubiquitous use of the saguaro as a symbol of the American Southwest, this excruciatingly slow growing cactus actually only grows in a small portion of the Sonoran Desert extending from extreme northwestern Mexico into south-central Arizona.
Like the Joshua tree in the Mojave, the saguaro is an integral part of the Sonoran Desert ecosystem. Birds such as the Gila woodpecker nest within the flesh of the cactus while the fruits and flowers provide a source of food for many other species, including humans. When the end finally comes for a saguaro (which can take well over 100 years), the flesh rots away to reveal an internal structure consisting of a series of wooden ribs, which often remain standing long after the saguaro dies:
Both the saguaro and Joshua tree face serious threats; in the long term from a climate that may change faster than they are able to migrate, and in the short term from a loss of habitat due to rapidly ballooning human populations in the desert regions that these giants inhabit.