In early October I photographed Joshua Trees and creosote soaking up the late-day sun on the footsteps of the Date Creek Mountains northwest of Wickenburg, Arizona.
The Joshuas in this area are the subspecies Yucca jaegeriana, which have notable differences compared to the Yucca brevifolia of Joshua Tree National Park. The U.S. Fish & Wildlife Service even recognizes brevifolia & jaegeriana as two distinct species, with Jaegeriana having slightly shorter leaves & arms that branch from the plant’s base. And unlike their California cousins, Yucca jaegeriana tend to be more compact and usually grow in denser stands. (See this map for the ranges of both species)
While most people associate Joshua Trees with California’s Mojave Desert, these remarkable plants actually range across several southwestern states — including Arizona, Nevada, and a small sliver of southwestern Utah. These desert dwellers can live for hundreds of years, with some estimated to be over 500 years old.
However, Joshua Trees face mounting challenges in our changing climate. While Yucca jaegeriana isn’t currently listed under the Endangered Species Act, Yucca brevifolia received protection under California’s Endangered Species Act in 2020 — marking the first time the state has protected a plant species due to climate change threats.
Both species face similar pressures: rising temperatures, prolonged droughts, and increasingly frequent wildfires are all impacting their livelihood. Joshua Trees require specific temperature conditions for their seeds to germinate, and young plants need occasional cold snaps to establish themselves. According to a study led by plant ecologist Lynn Sweet of UC Riverside, only 19% of their current habitat in Joshua Tree National Park may remain viable in year 2100.
If you ever find yourself traveling along Highway 93 between Wickenburg and Wikieup, keep an eye out for Yucca jaegeriana along the 7-mile stretch designated as the Joshua Tree Scenic Parkway. Their future may be uncertain, so its worthwhile to see these desert giants while they are still thriving.
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