Desert rose, botanical name Adenium obesum, is a plant that grows in sub-Saharan Africa and the southwest corner of Arabian Peninsula. Desert rose is a thick-bodied succulent that can live for hundreds of years. It has smooth branches with small glossy leaves, and it flowers most of the year in colors ranging from deep purplish red to pink and white. In their native environment, with cool, dry winters, they tend to go dormant in the winter. The plant grows from 4 to 6 feet tall and plants should be spaced 8 to 10 feet apart.
Desert rose like full sun and temperatures above 40 degrees Fahrenheit. If the temperature dips below 40 degrees, the branch tips are prone to damage. Temperatures lower than 35 degrees Fahrenheit will kill the plant. In climate that get temperatures that low, the plant should be grown in a container and brought indoors to winter over. The plant is hardy in zones 10 and 11.
Water is a concern for the gardener planning to plant desert rose: they don't like to be wet. In areas prone to flooding or heavy rain, desert rose should be planted in raised beds made by piling up rocks and stones into a berm 12 to 18 inches high. Cover this with a 2 to 3 inch layer of sand and topsoil at a ratio of 75 percent sand to 25 percent topsoil.
To plant, create a depression in the berm and plant the desert rose no deeper than it was in pot. Back fill with a soil-free potting mixture containing Perlite, sharp sand, or pumice. Make sure you don't damage the roots while planting to avoid rot. Do not use organic mulch with desert roses. Instead, spread small gravel or lava rock to make the area more attractive.
For the first three years, feed the plant every two weeks with a complete liquid fertilizer during the spring. In summer, switch to a slow release fertilizer formulated for palms. Apply once in early summer and again in early fall.
Water and Diseases
If temperatures are above 80 degrees Fahrenheit, then water should not be an issue, even in areas with heavy rainfall. Allow the plant to dry out completely between watering and discontinue watering when temperatures fall below 80 degrees Fahrenheit. Regular watering is only needed during times of the year when temperatures are greater than 80 degrees.
Desert rose is resistant to most diseases other than rot, but scale insects, mealy bugs, and spider mites can cause problems. Check pesticides carefully because desert rose is harmed by many sprays, especially those containing oils. Check with your county extension office if you have problems because they will have the most up-to-date information.