NPS/Paul Martinez Surrounded by twisted, spiky trees that look like something from a Dr. Seuss book, you might find yourself wondering—where are we? The traveler pulls over for a snapshot of this peculiar plant. The naturalist reaches for a field guide to decode its mystery. The rock climber, brushing past its dagger-like spines, yelps, “Yowch!” What Is a Joshua Tree?The Joshua tree (Yucca brevifolia) is the namesake of Joshua Tree National Park and a defining feature of the Mojave Desert. Once classified as a giant lily, modern DNA research has placed it in the Agave family. Like the California fan palm (Washingtonia filifera), the Joshua tree is a monocot—part of the same botanical group that includes grasses and orchids. At first glance, it’s easy to confuse Joshua trees with their close relative, the Mojave yucca (Yucca schidigera). A key difference? The Mojave yucca has longer, broader leaves with fibrous threads along the edges. While the Joshua tree is an iconic indicator of the Mojave Desert, it can also be found growing alongside saguaros in the Sonoran Desert of western Arizona or among pines in the San Bernardino Mountains. A Tree of Many NamesLong before settlers arrived, Native American communities recognized the Joshua tree for its many uses. The Cahuilla people, for example, referred to it as hunuvat chiy’a or humwichawa. Its tough leaves were woven into baskets and sandals, while its flower buds and seeds (either raw or roasted) were valuable food sources. In the mid-19th century, Mormon settlers gave the tree its common name, believing its outstretched branches resembled the biblical Joshua guiding them westward. However, historical records offer little evidence for this tale. Some theories suggest that pioneers saw the tree as a symbol of Joshua’s military leadership, its sharp leaves evoking the image of an armed force. A Survivor of the DesertJoshua trees are uniquely adapted to thrive in the arid, extreme conditions of the high desert. Their life cycle begins with the rare germination of a seed, often sheltered by the protective branches of a neighboring shrub. Growth is slow—after a brief early spurt, they settle into a steady pace of about ½ inch to 3 inches per year. The tallest Joshua trees in the park stretch over 40 feet into the sky, and while the average lifespan is thought to be around 150 years, some may be far older. Unlike traditional trees, Joshua trees don’t form growth rings, making age estimation difficult. Instead, researchers estimate age based on height and growth rate. 
NPS/Paul Martinez Blooming, Pollination and RegrowthIn spring, clusters of white-green flowers bloom at the tips of branches, but only under just the right conditions—well-timed rainfall and a crisp winter freeze. Scientists believe that freezing temperatures damage branch tips, triggering flowering and new branch growth. Some Joshua trees grow as single, unbranched stalks because they have never bloomed! Pollination relies on a sole an unlikely partner—the yucca moth. This small insect plays a crucial role by collecting pollen while laying eggs inside the flower. As the seeds mature, moth larvae hatch and feed on a portion of them. It’s a perfect partnership: the moth secures food for its young and the tree ensures the next generation of Joshua trees. Beyond seed dispersal, Joshua trees can also reproduce by sprouting from roots and branches. This ability helps them recover more quickly after natural disturbances like floods or wildfires. A Home for WildlifeThe Joshua tree isn’t just a symbol of the desert, it’s an essential part of the Mojave Desert ecosystem. Its branches and trunk provide shelter and nesting sites for many desert creatures. Look closely, and you might spot:
Joshua Tree FAQ’s The term “tree” describes the growth form of plants rather than a taxonomic group. Most Joshua trees fit the general definition of a tree—a woody perennial with a single trunk and branches. Interestingly, the eastern variety of Joshua trees tends to be more shrub-like and multi-trunked.
Joshua trees are native to the Mojave Desert but are not exclusive to Joshua Tree National Park. They can also be found in parts of California, Arizona, Utah, and Nevada, mainly within the boundaries and transition zones of the Mojave Desert. If you see a Joshua tree, you are likely in the Mojave!
The average lifespan of a Joshua tree is around 150 years, though some may live over 300 years. Extensive branching is often a sign of an older tree. Since Joshua trees don’t form traditional growth rings, researchers estimate their age based on height and branching patterns.
Most Joshua trees max out at around 40 feet tall, though some rare giants reach 50 feet. If you want to see some of the tallest trees in the park, head to the Covington Flats area.
Estimates suggest there are about 870,000 Joshua trees within the park.
Joshua trees typically flower for the first time when they reach about 50-70 years of age or around 2.5 meters (8 feet) tall. Blooms usually appear between mid-February and April, though unusual blooming events—like one in 2019—have been recorded as early as Thanksgiving.
Joshua trees thrive in cold winters, hot summers, and low precipitation. Researchers indicate they are restricted to areas where winter temperatures drop low enough to trigger their life cycle.
In Joshua Tree National Park, they are found at elevations ranging from 2,800 feet to 5,800 feet.
For an easy scenic drive, Park Boulevard offers stunning Joshua tree landscapes. There are multiple pullouts for quick views, as well as parking areas that lead to trails where you can walk among these iconic trees.
More Than a TreeWhether you’re accustomed to towering pines or leafy city parks, in the high desert, the Joshua tree is our tree. It stands as a symbol of survival, resilience and the beauty borne through perseverance. They are the silhouette that remind those of us who live here that we are home. Like the Lorax we speak for the trees, but often the trees speak to us. |
Last updated: March 23, 2025