The types of shrubs that occur across desert landscapes in the United States have made certain adaptations to exist in such harsh environs. The shrubs can often be identified by some of the features it possesses, or lacks, so it can survive in the desert.
A number of desert shrubs grow low to the ground, while others can attain the size of a small tree. For instance, the four-winged saltbush can be different heights, with some as short as 2 feet tall, while others are 15 feet high. The Crucifixion thorn often will be as tall as 10 feet. The creosote bush can be 12 feet in height, but is usually less than 4 feet tall.
Some desert shrubs have enough distinctive features that it makes their identification much easier. One such shrub is the four-winged saltbush, named for the seeds, which have four "paperlike wings" emerging at right angles, according to the Desert USA website. In addition to its seeds, the four-winged saltbush has leaves that have a salty taste to them, along with whitish tiny scales called scurf; these cover new growth and leaves to prevent water loss.
Studying the foliage on a desert shrub can make identifying the plant possible in some instances. The creosote bush, for example, is evergreen, with leaves always on some of its branches despite the conditions of its habitat. The pointed leaves are greenish-yellow, no more than ½ inch in length and both resinous and waxy. The creosote bush's leaves will have an obvious pungent aroma right after a desert rainstorm.
The form of desert shrubs reveals much about their identity. The leafless Crucifixion thorn has an elaborate network of branches tipped with sharp spines. The tumbleweed has a rounded appearance, with the younger plants having green shoots with purple or red striping. Once the tumbleweed shrub matures, it dries out and the rounded shape allows the wind to blow it about after it breaks off its stem. This also allows the tumbleweed to disperse its seeds.
Many desert shrubs occur in very specific habitats. The Crucifixion thorn, for example, develops in the stony desert washes and usually does not grow at elevations higher than 2,000 feet. The creosote bush prefers to develop on well-draining flatlands and slopes. It often grows in thickets of multiple bushes.