The Joshua tree (Yucca brevifolia) bestows the architectural majesty and character of the American Southwest. It sculpts the landscape and provides an important habitat and food source for numerous native species. The plant is a yucca and is native to the Mojave Desert. It is an adaptable plant that can tolerate USDA plant hardiness zones 6a to 8b. The Joshua tree is the largest of the yuccas. It is an evergreen perennial plant that starts out as a stem-less rosette and gradually grows a thick trunk decorated by sword-like leaves. The leaves grow in clumps off a scaffold of open ranging branches. The effect is bizarre, yet picturesque, and is a hallmark of the Mojave Desert. Leaves are up to 14 inches (35.5 cm.) long, sharply tipped and bluish green.
Water the Joshua tree once a month during hot, dry summers. Provide 1 inch of water to the plant's immediate root area, a circle around the tree with a diameter of at least 6 feet. Keep in mind that the yucca's thick trunk only extends 1 foot into the soil, and holds itself erect by roots and rhizomes that extend for 30 or more feet on all sides.
Trim back all vegetation that blocks sun from the Joshua tree to provide the plant with full sun. Use garden clippers or a pruning saw. Repeat annually.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils.
Trim back the flowering stem of the Joshua tree after it has wilted. Avoid pruning out the dead leaves that insulate the plant and absorb moisture.
The roots contain saponins. Whilst saponins are quite toxic to people, they are poorly absorbed by the body and so tend to pass straight through. They are also destroyed by prolonged heat, such as slow baking in an oven. Saponins are found in many common foods such as beans[K]. Saponins are much more toxic to some creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish
