Mustard trees (Salvadora persica) are small trees and bushes that are native to the Middle East and Africa. Mustard trees can be cultivated in parts of the United States that are hot and have low humidity. The mustard tree does not produce the seeds used to produce the popular condiment mustard.
Mustard trees are considered evergreen shrubs, according to Kansas State University. When fully grown, mustard trees can reach up to 20 feet in height.
Mustard trees have an irregular shape, being just as wide as they are tall. The shrub's branches grow very low to the ground and produce oval leaves. When the tree flowers, it blooms in green and yellow blossoms.
In the U.S., mustard trees grow best in USDA hardiness zones 7 through 11. They will grow tall without much water and, when mature, the mustard tree produces a fleshy, but very sweet, fruit.