« Browse By Botanical Name

Adenium obesum

Accession Count: 1
Common Name: desert rose
Family Name: Apocynaceae
Botanical Name: Adenium obesum
Sub Species:
Variety:
Forma:
Cultivar:
Characteristics: A. obesum is a succulent shrub to small tree that possesses thick stems, a swollen caudex, and an open crown of glaucous leaves, arranged in spirals at branch tips (1, 2). However, trees are often leafless, being deciduous during the dry seasons, even in cultivation (3). Branches are smooth, irregularly thickened and spaced, occasionally weak and spreading (2). During the summer, satisfied succulents will develop terminal clusters of showy, bell-shaped flowers – pink to red, and occasionally white or with white centers (1). Flowers are salverform, possessing a long tube, five spreading lobes, and five protruding stamens (1).  After 2-3 days, blooms will perish, and will be eventually followed by pale gray to brown fruits – twin follicles that are united at the base, resembling the horns of an ox (1, 2). Once mature, the fruits will open to release the long, narrow seeds, which possess a dirty-white to golden-brown apical tuft for wind dispersal (2).
Compound: Ade obe
Geographic Origin: Africa
Ecozone Origin:
Biome Origin:
Natural History: The desert rose was first named Nerium obesum by Pehr Forsskål, who included it within the 1775 Flora Aegyptiaco-Arabica 205 (4). However, in 1819 the current name, A. obesum, was designated by Johann Jakob Roemer and Josef August Schultes, and included within Systema Vegetabilium 4:411 (1819) (5). The genus, Adenium, is the Latin name for the Arabic oddaejn, “of Aden”, referring to the location where the plant was originally found. The specific epithet, obesum, derives from “obese” or “swollen”, for the plant’s enlarged caudex (6).
The desert rose is widespread across the warm, arid, and tropical regions of east and northeast Africa, the Arabian peninsula, and Madagascar, and has naturalized in Sri Lanka and Thailand (2, 3, 6, 7). It persists in rocky and sandy soils within savannahs, dry bushland, woodland, and wooded grassland, preferring habitats with frequent summer precipitation and dry winters (2, 8).
Cultivation Notes: A. obesum persists in USDA hardiness zones 10a to 11 (30-40°F), but is frost intolerant and should not be exposed to temperatures below 50°F for long periods of time (7, 9). To avoid winter deciduousness, maintain 60°F or higher (10). Overall, the desert rose will tolerate temperatures up to 100°F, but flowering will stop after 100°F is exceeded (8, 11). While A. obesum appreciates sun, the species is very susceptible to scalding, and should be protected. However, too much shade will also lead to leggy growth and reduced flowering – provide light shade or filtered sunlight for the best results (2).
Water moderately during spring and summer, providing irrigation in the early mornings, and reducing watering in the winter (2, 7). Do not allow the soil to become waterlogged, but provide enough moisture to encourage flowering and maintain leaves during the winter (10). A. obesum should be sited in a very porous succulent soil or regular potting mix supplemented with pumice, perlite, sand, or vulcanite (2, 7). Additionally, maintain a pH between 6.0 and 7.0, ideally as close to 6.0 as possible (7). The container should be chosen carefully, as an oversized pot will lead to excess root growth and limited blooms (7, 11). At the same time, A. obesum that are planted in overly deep pots will develop a carrot-shaped underground caudex. Ensure that the major trunk is planted with the roots below the caudex line for the best results (2).
If unusual growth is desired, the desert rose can be developed as a bonsai or grown upside down. To grow upside down, prune excess twigs and branches, remove the plant from its container, wash the root ball, and repot with the head in the soil and the roots emerging. Over time, sprouts, leaves, and even blossoms will develop from the sides of the root mass, forming a unique centerpiece (11). Often, the roots are “lifted” and exposed outside of the soil, to display the sculptural root and caudex design (12). Propagation is possible through seed, grafting, or cuttings (9). Seed is the most commonly used, and will result in plants that resemble the parents at a young age. However, plants grown from cuttings will not develop the swollen caudex – or the stems will only develop underground, and will later need to be exposed (10, 13).
Ethnobotany: When wounded, A. obesum exudes a toxic latex that has been utilized extensively in Africa as a piscicide and poison, often to douse arrows by the Swahili people (14). At the same time, the desert rose can be used for fuel or as a living fence (8).
Despite its toxicity, A. obesum possesses anticancer, antiviral, antibacterial, and antioxidant properties, and has been used for a variety of medicinal purposes (15). A root decoction is used to treat venereal diseases and rhinitis (stuffy nose), while a root or bark extract is capable of treating skin diseases and killing lice. Other uses include as an abortifacient, and the treatment of decaying teeth and septic wounds through application of the latex. The toxicity of the desert rose adds additional ethnobotanical value, being used against Bacillus subtilis, carcinoma cell lines, Amblyomma spp., Boophilus spp., and lice (8).
Height: 6 - 10 feet
Width: 0 - 5 feet
Growth Rate: Slow Growing
Grow Season: ForeSummer
Flower Season: ForeSummer
Color: Pink
Function: Patio
Spread: Non-spreading
Allergen: Allergenic
Invasive: Benign
Toxicity: Toxic
Hardy: Tender
Water Use: Moderate Water Use
Citations:
  1. Missouri Botanical Garden. Retrieved March 4th, 2021.
  2. Llifle Encyclopedia of Succulents. Retrieved March 4th, 2021.
  3. Oregon State University. Retrieved March 4th, 2021.
  4. Tropicos Nerium obesum. Retrieved March 4th, 2021.
  5. Tropicos Adenium obesum. Retrieved March 4th, 2021.
  6. Monaco Nature Encyclopedia. Retrieved March 4th, 2021.
  7. The Spruce. Retrieved March 4th, 2021.
  8. Useful Tropical Plants. Retrieved March 4th, 2021.
  9. Dave’s Garden. Retrieved March 4th, 2021.
  10. World of Succulents. Retrieved March 4th, 2021.
  11. Plant Desert. Retrieved March 4th, 2021.
  12. University of Florida. Retrieved March 4th, 2021.
  13. Plant Care Today. Retrieved March 4th, 2021.
  14. Dr. Duke’s Phytochemical and Ethnobotanical Databases. Retrieved March 4th, 2021.
  15. Researchgate. Retrieved March 4th, 2021.
Alert

Adenium obesum