The desert rose (Adenium obesum (Forsskal) Roemer & Schultes) is native to sub-Saharan Africa and Arabia. Depending upon the authority, desert roses are a single species with eight subspecies or are several species. Desert roses are members of the Apocynaceae or dog bane family and contain several cardiac glycosides. According to Lewis and Elvin-Lewis (Medical Botany, 1977), the plant "is used as a fish and arrow poison in eastern Africa. It is very toxic to livestock."
Desert rose are not finicky plants, although they have received that reputation. The plants normally grow in climates with summer rains and dry winters. They prefer frequent fertilization and should never be allowed to freeze. Desert rose sometimes suffer from scale and spider mites, but the only pest I've noticed is the oleander moth caterpillar which strips foliage and flowers.
Adenium were named for Aden (the former name of Yemen, Oddaejn in Arabic) by Johann J. Roemer and Joseph A. Schultes. Pehr Forsskal, the first European to see the desert rose, was almost a footnote in history. By odd coincidence, Roemer was born the year Forsskal died presumably of malaria.
Pehr Forsskal entered the university at Uppsala when he was 10 years of age. Besides studying botany under Linnaeus, he was also a student of philosophy and theology. In an age where everyone knew their place; Forsskal submitted a thesis on civil liberty. His 'presumptuous' paper was confiscated by Linnaeus and condemned by every church.
In 1761, Forsskal joined an expedition with five others funded by the King of Denmark to explore Egypt, Arabia, and India. After nine months in Egypt, the team landed in Yemen late in December 1762. Pehr Forsskal passed away in his 31st year on July 11, 1763. Of the six who started the expedition only one, Carsten Niebuhr, survived.
Niebuhr did something remarkable. Even after all his team mates died, he carried on and completed the mission of the expedition. Through it all, he kept the journals and collections. After an absence of seven years, Niebuhr returned to Copenhagen with the expedition's information.
