Although the Joshua tree was named after the Biblical prophet Joshua, the tree was never mentioned in the Bible. It is native to the Americas rather than the Middle East.
The Joshua tree, also known as the "yucca palm," from its scientific name, Yucca brevifola, is found mostly in the Mojave Desert and other areas in the American West. Folk legend traces the name to Mormon settlers in these areas in the 19th century who saw the tree's gnarled branches and compared them to outstretched arms leading them forward. This could compare to several instances where the Biblical figure Joshua lifted his arms upward, such as Joshua 8:12. Other sources point out the conception of the American West as a promised land for many religious settlers, suggesting that the name Joshua was applied to these distinct trees since Joshua was Moses' successor in leading the Biblical Israelites to their own promised land.
However, 19th-century sources are mixed on this subject, although most of the earliest available uses of the name do treat it as emerging within the Mormon community. Some religious origin for the term Joshua tree seems likely, as both Mormon and other Christian settlers often saw their new homes through a Biblical lens, but like many slang terms, the exact origin is unknown.