Desert Rose (Adenium obesum) is a species of flowering plant in the dogbane family, Apocynaceae, that is native to the semi- arid, sub-Saharan regions of eastern and southwestern Africa plus the Arabian peninsula. Other Common names include Desert Azalea, Mock Azalea, Sabi Star, Impala Lily and Kudu Lily.
In the Garden
In the wild, this plant will eventually rise to 6-9′ tall, but will grow much smaller in containers. In the wild, flowers bloom in summer with some irregular continued bloom throughout the year. As houseplants, flowers typically bloom only in summer. Milky plant sap is poisonous.
- This plant is resistant to deer.
Caring & Growing
Adeniums are relatively easy to care for as long as you think of your plant as actually being two quite different plants with different requirements at different times of the year. In the warmth of summer, while in full growth, they should be treated as a tropical plant, watered abundantly and frequently and fertilized with a fair amount of generosity. In the winter time they need a dry rest, and should be treated like a cactus, with only light occasional waterings during warm bright days. In containers, desert rose is best grown in a loose, sandy or gravelly, well-drained soil mix in full sun. Regular applications of fertilizer in spring will help promote flowering. Plants can be left outdoors in sunny locations during the summer.
Winter hardy to USDA Zone 11. South of USDA Zone 11, Adeniums should be grown in containers and overwintered indoors. As soon as temperatures begin to dip below 55 degrees in autumn, bring containers indoors to sunny but cool locations with reduced watering. In warmer areas in the Southern region, a covered porch near the house can work for overwintering Adeniums. However, if outside temperatures are expected to drop to the twenties, outside plants under should be moved or covered. Plants usually lose their leaves in winter and go into a dormancy-like period at low temperature. During dormancy, plant is to be kept completely dry (both from rain and watering) and absolutely frost free.
Adenium obesum needs the maximum amount of light available, up to and including full sun, during its growing season. During this time Adeniums should be grown in very bright light; and if the plant is large enough, in full, blazing sun. As a general rule, if the plant requires a ten-inch or larger pot, it should do well in full sun; otherwise, it should be grown under filtered sunlight like that under the canopy of a branched tree. At the end of the growing season, with the lowering of temperatures, Adeniums will drop their leaves and go dormant. They do not need much light at this time, but they should not be put in the dark.
Adeniums should be potted in a well-drained soil mix. Any light commercial mix can start as a base, but should be augmented with about 1/3 to 1/2 drainage material such as coarse (screened and washed) sand, clean poultry grit, gravel, or sponge rock (such as Perlite). If you use a peat-based mix, you should repot into fresh soil about every two years. Planting container must have good drainage (be sure the saucer doesn’t retain water). The pot should only be a bit larger than the size of the root mass. Increase the pot size every year or two until the plant achieves the desired size.
Apply regular moisture during periods of growth, but allow soils to dry between waterings. Adeniums, like all succulent plants, have the ability to store water. In their native habitat they live and grow only on the available rainfall, storing water in wet times to sustain them through drought. In extreme drought, even during the growing season, they can drop their leaves and become “drought dormant”, only to re-leaf with the first available moisture. These arid conditions do not adversely affect the plants other than to cause them to grow more slowly.
Adeniums respond well to generous and regular fertilizing. Prefer time released fertilizer over liquid feed. Always water Adenium slightly before feeding in order to avoid leaf drop and root burn. Fertilize plant espacially after it flowers. Adeniums can be fertilized with what amounts to a full strength application of a general purpose fertilizer every two weeks. Alternatively, under most home conditions, and only if the plant is healthy, a half strength solution applied once a month during the growing season (April – October) of any available house plant food will be adequate.