The key to desert plants’ survival depends on adaptations to dry conditions. Desert plants boast several different growing methods that make the most of the climate’s limited rainfall while enabling plants to thrive in glaring sun, rocky or clay soil, and strong wind. The desert plant family includes cacti, shrubs, grasses, flowers, and trees—greenery you would see in any other environment. In addition, semitropical and tropical plants often thrive in desert regions, injecting a splash of color into the scenery. By filling a landscape with a variety of desert plants, you can create an inspired and striking design.
Ways Desert Plants Survive
Because desert regions offer minimal rainfall, desert plants have special ways to collect, conserve, and store water. In a home landscape, once established, these same plants can survive with little to no supplemental irrigation.
Collecting Water
Desert plants capture rainfall through adaptations in their leaves and roots. Cacti typically have large, shallow root systems that radiate out from the plant in a circular pattern. This allows a cactus to absorb extensive amounts of water each time it rains. Many succulents, including sedums, have leaves arranged in a rosette that catches and holds water, allowing the leaves to continue to absorb water after bouts of rain. Some plants also have saucer-shaped leaves that retain water. A special group of desert plants, known as phreatophytes, have long roots that reach deep into soil to tap underground water tables. Mesquite trees (Prosopis species), including screwbean mesquite, honey mesquite, and velvet mesquite, belong to this group. The roots of some mesquite trees have measured up to 80 feet long.
Storing Water
Many desert plants store water in their stems. For some species, this stored water enables plants to survive for years on moisture gathered during a single rainfall. Some cacti and succulents feature ribbed stems, which expand as plants absorb water and contract as plants consume water. Cacti have a waxy covering, or skin, that seals water into the plant, so it doesn’t evaporate. One purpose of the spines on cacti is to protect the plant against creatures that would try to open the stem to consume water reserves.
Conserving Water
An unusual adaptation of desert plants to limited water is the ability to speed through a life cycle—from dormancy to full flowering and setting seed—following rainfall. Desert plants that do this are called ephemerals, or annuals. Ephemerals include many desert wildflowers, such as desert paintbrush (Castilleja), Mojave woodyaster (Xylorhiza), and desert sand verbena (Abronia). These plants spring to life after winter rains, coloring the spring desert with bright blooms. Ephemeral desert plants scatter seed and slip into dormancy before summer heat builds.
Other Adaptations
Desert plants also have other ways they cope with the extreme heat. Gray or silver foliage reflects sunlight and keeps plants cooler. Green stems conduct photosynthesis, which means leaves can disappear. For some desert plants, like the palo verde tree (Cercidium), summer signals a time of dormancy, and plants drop their leaves. The green stems continue to feed roots and keep the plant alive until vital moisture arrives, fueling the formation of new leaves. Tiny hairs covering leaves and stems trap the smallest amount of moisture and slow evaporation. Cactus spines are modified leaves with a limited surface area that reduces water loss. Spines also help shade stems.
Desert Plants for Other Climes
Even if you don’t live in an arid region, you can still make desert plants a part of your garden. In cooler climes, try growing desert plants in containers. Click here for ideas.
