WebNerium oleander (/ ˈ n ɪər i ə m ... / NEER-ee-əm), commonly known as oleander or rosebay, is a shrub or small tree cultivated worldwide in temperate and subtropical areas as an ornamental and landscaping plant. It is the only species currently classified in the genus Nerium, belonging to subfamily Apocynoideae of the dogbane family Apocynaceae.It is so widely cultivated that no precise ...