Cacti, shrubs, and trees grow in abundance in the Sonoran Desert. Temperatures in the Sonoran Desert can reach 120 degrees Fahrenheit and rainfall is less than 10 inches per year. Plants in the desert need to adapt to an environment of little rain and very hot temperatures.
It takes thousands of years and many generations to change what a plant looks like and how it functions. Cacti adapted to the arid land by being able to store large amounts of water in their flesh. Their leaves became spines to help reduce evaporation and discourage animals from eating them. Some shrubs, like the saltbush, have silvery leaves that help retain moisture. The ocotillo and creosote bush lose their leaves entirely during drought periods, reducing moisture loss.
One reason palo verde, mesquite, and other trees survive in the desert is because their leaves are very small. The palo verde tree can continue the photosynthesis process without any of its leaves, because its green trunk and branches contain chlorophyll.
Because of the harshness of the environment, many desert plants grow very slowly, but they can also live a long time. Many cacti can be over a hundred years old and some clumps of creosote bush are believed to be several thousand years old!
Last updated: May 19, 2019