About Adenium obesum (Forssk.) Roem. & Schult.
Adenium obesum (Forssk.) Roem. & Schult. is an evergreen or drought-deciduous succulent shrub. It may also drop its leaves during cold snaps, and leaf retention can vary depending on subspecies or cultivar. This plant grows to between 0.12–5 m (0.39–16.40 ft) in height, with disproportionately large pachycaul stems and a thick, swollen basal caudex (a protruding rootstock that sits above the soil line). Its leaves are arranged in a spiral pattern, clustered near the tips of new growth, are simple with smooth entire margins, have a leathery texture, and measure 5–15 cm (2.0–5.9 in) long and 1–8 cm (0.39–3.15 in) wide. The flowers are tubular, 2–5 cm (0.79–1.97 in) long, with an outer portion 4–6 cm (1.6–2.4 in) across and five petals. The flowers resemble those of related genera including Plumeria and Nerium, and are most often red or pink, frequently with a pale whitish marking on the outer part of the flower throat. In ecology, caterpillars of the polka-dot wasp moth (Syntomeida epilais) feed on this species, alongside feeding on oleanders. In regions with consistently warm temperatures year-round, Adenium obesum can bloom continuously. Adenium obesum produces sap in its roots and stems that contains cardiac glycosides. Across much of Africa, this sap is used as arrow poison for hunting large game, and also as a toxin to catch fish. In cultivation, Adenium obesum is a popular houseplant and bonsai in temperate regions. It needs a sunny growing location, and a minimum winter indoor temperature of 10 °C (50 °F). It grows well with the dry, infrequent watering regime that cacti require. It is typically propagated by seed or stem cuttings. The many cultivated hybrids are most often propagated by grafting onto seedling rootstock. Plants grown from seed are more likely to develop a swollen caudex when young, but over time, many cutting-grown plants cannot be told apart from seed-grown plants. Like many plant species, Adenium obesum can also be propagated via in vitro plant tissue culture. This plant has been awarded the Royal Horticultural Society's Award of Garden Merit.
