Joshua Tree

The Joshua tree is the signature plant of the Mojave Desert, a giant arborescent yucca that can live for well over a century and reach 40 feet tall. Despite its tree-like stature it is a monocot related to agaves and lilies, not a true tree, and it lacks growth rings.

Its twisted, branching silhouette — said to have reminded Mormon pioneers of the prophet Joshua raising his arms — is unmistakable. Growth is extremely slow, and the species depends on a remarkable, exclusive partnership with the yucca moth for pollination.

Bayonet leaves and branched arms are diagnostic:

• Leaves stiff, sharp, bayonet-like, 6-14 in long, blue-green, clustered in dense rosettes at branch tips; old dead leaves hang as a shaggy 'skirt' on the trunk
• Trunk and limbs thick, fibrous, and irregularly branched after each flowering or injury, giving the gnarled form
• Flowers creamy greenish-white, cup-shaped, in large dense clusters atop branches in spring (only after sufficient winter rain and cold)
• Fruit spongy, oval green capsules
• Size typically 15-40 ft tall, very slow-growing

A true desert plant needing heat, sun, and sharp drainage.

• Light: Full sun
• Water: Very little once established; rot-prone with excess moisture
• Soil: Fast-draining sandy or gravelly desert soil; never soggy
• Temperature: Hardy in USDA zones 6-10; needs hot days, cool nights, and a winter chill to bloom
• Feeding: Not needed
• Propagation: From seed (slow) or offsets and stem/rhizome cuttings; transplanting mature wild plants is difficult and often prohibited

Native and largely endemic to the Mojave Desert of the southwestern United States — parts of California, Nevada, Arizona, and Utah — typically at 2,000-6,000 ft elevation. It gives its name to Joshua Tree National Park.

It grows in open desert grassland and scrub, often in extensive stands. Climate change and habitat loss threaten its long-term range, making it a focus of conservation concern.

Primarily valued ecologically and as a desert landscape icon. Its flowers, fruit, and structure support numerous desert animals, and it forms an obligate mutualism with the yucca moth, its sole pollinator.

Indigenous peoples used the tough leaf fibers for sandals, baskets, and rope, and ate the seeds and flower buds. Today it is a prized xeriscape specimen and a major draw for desert tourism and photography.