Plants in desert ecosystems have adapted to dry, hot climates by altering their physical structure so they can store and conserve water. Some desert plants have few to no leaves, which helps to reduce water loss. Other plants grow very long roots, which allow them to obtain moisture from deep within the earth. Despite the harsh conditions of North America's deserts, various perennials and annuals thrive in the desert environment.
The barrel cactus (Ferocactus wislizeni) has a cylindrical body that reaches up to 11 feet tall. The pleated stem expands and contracts depending on water availability. The 2-inch wide flowers bloom in bright reds, oranges and yellows during the summer. The barrel cactus bears yellow, tart fruit that is sometimes used to make cactus candy. This cactus grows in the Chihuahua, Sonoran and Mojave deserts.
Brittlebush plants (Encelia farinose) commonly grow in the Sonoran and Mojave deserts. This deciduous shrub forms a low, domed mound with brittle branches sprouting from its woody trunk. The leaves are covered with grayish-green hairs that trap moisture and insulate the leaves against extreme temperatures. The spectacular yellow flowers add vibrant color to desert landscapes from March until June.
Chainfruit cholla (Opuntia fulgida), sometimes called jumping cholla, is a shrubby cactus that commonly reaches 8 feet tall and 6 feet across. This cactus has a central trunk that sprouts numerous drooping branches covered in sharp spines. Those spines have sheathes that reflect sunlight and prevent the plant from overheating. The pink flowers bloom from June until August. Chainfruit cholla plants thrive in the Chihuahua and Sonoran deserts.
The creosote bush (Larrea tridentate) earned its name because it smells similar to commercial creosote tar. This Sonoran Desert bush bears small, pointy leaves covered with a varnish. The yellow flowers bloom along the stems from February until August. Creosote bushes typically grow from 3 to 10 feet in height, depending on the amount of water present.
Desert ironwood (Olneya tesota), also called Arizona ironwood, is an evergreen tree that only grows in the Sonoran Desert. This plant belongs to the pea family (Fabaceae), and the flowers and leaves are similar to those of the sweetpea. These slow-growing plants reach heights up to 30 feet and spread up to 25 feet. Desert ironwood is often called the “nurse plant” because it shelters so many plants and animals underneath its thorny, low-hanging branches. The lavender flowers bloom from April until June.
The Joshua tree (Yucca brevifolia) is the characteristic plant of the Mojave Desert. The Mormon pioneers named this tree after a Christian profit, believing the tree was pointing their way to the Promised Land. The Joshua tree grows from 5 to 40 feet high, but only has a diameter of 1 to 3 feet. This tree blooms creamy white, bell-shaped flowers from March through May.
Mojave asters (Xylorhiza tortifolia) are perennial plants of the Asteraceae family. These plants reach about 30 inches high and have long, grayish-green stems. The narrow, lavender to dark purple petals surround a yellow central disk. These flowers typically appear from March until May. The Mojave aster grows in the Mojave, Sonoran and Great Basin deserts.