Whole Plant
Common Name: Joshua tree
Type: Broadleaf evergreen
Family: Asparagaceae
Native Range: California, Nevada
Zone: 6 to 10
Height: 15.00 to 30.00 feet
Spread: 15.00 to 30.00 feet
Bloom Time: March to May
Bloom Description: Creamy white
Sun: Full sun
Water: Dry
Maintenance: Low
Flower: Showy
Leaf: Evergreen
Attracts: Birds
Other: Thorns
Tolerate: Deer, Drought, Dry Soil, Shallow-Rocky Soil
Culture
Best grown in dry, coarse, well-draining soils in full sun. In the wild this plant thrives in extreme desert conditions, with 3-14" of annual precipitation, summer high temperatures around 120°F and winter low temperatures of -13°F. For these reasons, supplemental watering should only be supplied during prolonged drought conditions, and should be limited to one thorough soaking per month. Hardy in Zones 6-10.
Noteworthy Characteristics
Yucca brevifolia, commonly known as Joshua tree, is a large, slow-growing, evergreen, tree form yucca native only to the Mojave Desert of the southwestern United States. It is found growing at elevations between 1,600-7,200' on open, rocky grasslands where they visually dominate the landscape. Mature individuals usually reach around 15-30' tall (sometimes to 50' or more) with an open, rounded canopy of equal width. The average lifespan of a Joshua tree is estimated at 150 years, but older trees exceeding 300 years old have been recorded. Younger plants lack the distinctive branching of older specimens. The stiff, narrow, tapered leaves (between 6-14" long and 0.25-0.5" wide) have terminal spines and small serrations along the margins. The foliage forms rosettes on the ends of the branches, and desiccated leaves remain on the plant covering the trunk and stems. The creamy white, round to ovate flowers (up to 2" long and 1" wide) are borne on terminal panicles (up to 20" long). Light green seedpods (up to 4" long) mature on the tree in clusters. In their native habitat, Joshua trees are an important source of food and shelter for wildlife. Many birds utilize the branches for nesting and perching. These include cactus wrens, northern flickers, and American kestrels. A single moth species called the yucca moth pollinates the flowers. Small mammals such as antelope squirrels and kangaroo rats eat the seeds. Joshua trees were also used by the Cahullia people of inland southern California as a source of food and fibers.
Genus name comes from the Carbi name for manihot, also called cassava or yuca, which is not closely related but has similarly enlarged root structures.
The specific epithet brevifolia means "short leaves", in reference to the length of the foliage relative to other yuccas.
According to commonly held legend, the name Joshua tree was given by Mormon settlers and refers to the biblical tale of Joshua guiding the Israelites in the battle for Ai with an outstretched arm.
Problems
No known pest or disease problems. Deer do not bother this plant.
Uses
Suitable for desert gardens, xeriscaping, rock gardens, and other dry sites. Makes for an excellent specimen piece. When purchasing seeds or plants, communicate with the supplier and verify that they were sourced responsibly and not collected from vulnerable, wild populations.