Adenium obesum
Culture
Winter hardy to USDA Zone 11. North of USDA Zone 11, plants should be grown in containers and overwintered indoors. In containers, desert rose is best grown in a loose, sandy or gravelly, well-drained soil mix in full sun. Plants have excellent heat tolerance. Apply regular moisture during periods of growth, but allow soils to dry between waterings. Regular applications of fertilizer in spring will help promote flowering. Plants can be left outdoors in sunny locations during the summer. As soon as temperatures begin to dip below 55 degrees F. in autumn, bring containers indoors to sunny but cool locations with reduced watering. Plants usually lose their leaves in winter and go into a dormancy-like period. For container plants, the best caudex usually develops from seed-grown plants.
Noteworthy Characteristics
Adenium obesum, commonly called desert rose, is a thick-stemmed sparsely-leaved perennial succulent that is native to semi- arid, sub-Saharan regions of eastern and southwestern Africa plus the Arabian peninsula. In the wild, this plant will eventually rise to 6-9' tall, but will grow much smaller in containers. It forms a broad, swollen, often grotesque caudex (usually partially buried underground) from which rise twisted leafless gray-green to brown branches. Leathery, spirally-arranged, fleshy, ovate, gray-green leaves (to 4" long) appear at the stem tips. Narrow, bell-shaped, salverform flowers (to 2" across), each with five spreading lobes and five protruding stamens, are red, pink or rose with white to pale yellow throats. In the wild, flowers bloom in summer with some irregular continued bloom throughout the year. As houseplants, flowers typically bloom only in summer.
Genus name is the Latinized Arabic name aden used for Adenium obesum.
Specific epithet means fat or succulent.