The desert ecosystems within the borders of the United States do have the ability to support a wide selection of different plants. While most people immediately conjure up images of cacti when contemplating desert plants, the truth is that there are also wildflowers and trees that exist in this region. The wildflowers often depend on the fickle rainfall habits of the desert to grow and then bloom, while the trees have made adaptations in order to maintain a foothold in the desert.
The cacti that grow in the Southwest are a varied lot, with some as tall as the saguaro, which can attain 50 feet in height, and as small as the prickly pear, which sometimes just grows a foot high. The spines that grow on cacti are also different from species to species. The fishhook cactus has spines that do resemble a fishhook, curved at the end while the hedgehog cactus features straight or curved spines an inch or two in length. Cacti species in the desert often have names that give an individual a clue to their shape, such as the beavertail cactus, the barrel cactus and the organ pipe cactus.
Trees and Shrubs
The trees and shrubs that can survive the lack of water and typically poor soils of the desert do so in different ways. Many, like the mesquite, will have long roots that can access water with the roots sometimes being longer than the tree is tall. The creosote bush has leaves that conserve water and withstand the heat, while the Joshua tree is unique in that only a certain type of moth can pollinate it. The cottonwood tree will normally grow near some source of desert water, above or below ground. Other species of shrubs or trees in the American deserts include the tumbleweed, the desert willow, the elephant tree, the greasewood tree and the Ponderosa pine.
The desert sometimes comes alive after a rainfall as many types of wildflowers whose seeds lie dormant waiting for the right mix of water and sun, suddenly germinate and produce a plant with an accelerated lifespan. These wildflowers grow fast and bloom quickly while they can before scattering their seeds into the desert where they will await the same opportunity to grow. Other wildflowers tough it out year after year in the desert, such as the desert lily, which develops from a bulb and can grow as tall as 4 feet. Some of the wildflowers of the desert include the fairy duster, the ghost flower, the desert lupine, the Mojave aster, the Arizona poppy, the desert five-spot and the popcorn flower. Many cacti have very prominent and brilliant flowers, as well.