Phoenix, Arizona is set in the upland Sonoran desert, an ecosystem described as "lush," "hot," and "varied" by the Sonoran Desert Naturalist website. Far from being a stereotypical desert devoid of plant life, the Sonoran desert is home to a wide variety of indigenous plants and flowers. The region receive from four to 11 inches of average annual rainfall during two yearly rainy seasons, conditions that are conducive to succulent cacti and drought-tolerant shrubs, trees and flowering plants.
Many varieties of flowers can thrive in the Phoenix area at different times of year. For the best results, stick to native flowering plants, which tend to be hardy and drought-tolerant. Indigenous varieties include desert lilies, blue sand lilies, blue dicks, golden eyes and Mexican poppies. The Arizona Cooperative Extension recommends planting varieties such as bee balm, black-eyed Susans, cosmos, desert marigolds, English daisies, snapdragons and sunflowers.
Indigenous options, as recommended by the Arizona Native Plant Society, include desert sunrise, desert anemone, desert clematis, desert honeysuckle and desert hibiscus. To ensure the health of your desert flowers, the Desert Botanical Garden recommends incorporating four to six inches of organic compost matter into clay or compacted soil to a depth of six to eight inches. Water your seedlings every other day until plants have more than five leaves, then soak them once a week.
Citrus trees can thrive in Phoenix with the right care. The Arizona Cooperative Extension recommends planting citrus trees such as lime, grapefruit, orange and lemon in March. Plant smaller trees, from two to five years old, as they tend to transplant more successfully, and don't expect fruit for about three years after you transplant a citrus tree. Citrus trees naturally shade their own trunks from the sun; if you must trim your tree's lower branches, you'll need to wrap or paint the exposed trunk white to prevent sun damage. Water every one to two weeks during the summer and every four to six weeks during the winter. Use a basin or flood irrigation method for deep watering.
The Arizona Native Plant Society recommends planting indigenous shrubs that can survive mostly on annual rainfall and require very little extra irrigation. Such species include Indian mallow, prairie acacia, Wright's bee bush, false indigo, Baja fairy duster and Mexican crucillo. Most shrubs do well in well-drained, sandy soil with a layer of mulch on top. Let the plants dry out in between waterings and use a deep-soaking method.
Cacti grow throughout the Sonoran desert and require little maintenance. In fact, one of the worst things you can do for your cactus is water it. The only time you should water a cactus is if the temperature has been over 105 degrees and no rain has fallen for over a month. The Desert Botanical Garden recommends planting succulent varieties such as adeniums, agaves, aloes, euphorbias or lithops. Succulents do best in sandy, loose, well-drained soils.