Nerium oleander L., Sp. Pl. 1: 209 (1753)

(Latin for 'oleander, the common name in Europe (Spain and Italy)')

Nerion oleandrum St.-Lag.
Nerium carneum Dum.Cours.
Nerium flavescens Spin
Nerium floridum Salisb.
Nerium grandiflorum Desf.
Nerium indicum Mill.
Nerium indicum subsp. kotschyi (Boiss.) Rech.f.
Nerium indicum var. leucanthum Makino
Nerium indicum forma leucanthum (Makino) Okuyama
Nerium indicum var. lutescens Makino
Nerium indicum forma lutescens Makino
Nerium indicum var. plenum Makino
Nerium japonicum Gentil
Nerium kotschyi Boiss.
Nerium latifolium Mill.
Nerium lauriforme Lam.
Nerium luteum Nois. ex Steud. [Invalid]
Nerium mascatense A.DC.
Nerium odoratissimum Wender.
Nerium odoratum Lam.
Nerium odorum Aiton. Nerium odorum Sol.
Nerium oleander var. indicum (Mill.) O.Deg. & Greenwell
Nerium oleander subsp. kurdicum Rech.f.
Nerium splendens Paxton
Nerium thyrsiflorum Paxton
Nerium verecundum Salisb.
Oleander indica (Mill.) Medik.
Oleander vulgaris Medik.

Shrub to small tree up to 6 m tall, with poisonous white sap. The leaves are in pairs or whorls of three, thick and leathery, dark green, narrow lanceolate, 521 cm (2.08.3 in) long and 13.5 cm (0.391.4 in) broad, and with an entire margin. The flowers grow in clusters at the end of each branch; they are white, pink to red, 2.55 cm diameter, with a deeply 5-lobed fringed corolla round the central corolla tube. They are often, but not always, sweetly scented. The fruit is a long narrow capsule 523 cm long, which splits open at maturity to release numerous downy seeds.

It typically occurs around dry stream beds on poor soils. It tolerates dry conditions well. Some invertebrates are known to be unaffected by oleander toxins, and feed on the plants. Caterpillars of the Oleander or Polka-Dot Wasp Moth (Syntomeida epilais) feed specifically on oleanders and survive by eating only the pulp surrounding the leaf-veins, avoiding the fibers. Larvae of the Common Crow Butterfly (Euploea core) also feed on oleanders. The Common Crow larvae retain or modify toxins, making them unpalatable to would-be predators such as birds, but apparently not to other invertebrates such as spiders and wasps.

It is so widely cultivated that no precise region of origin, perhaps in southwest Asia, has been identified. It is native or naturalized in a broad area from Mauritania, Morocco and Portugal eastward through the Mediterranean region and the Sahara (where it is only found sporadically), to the Arabian peninsula, southern Asia and as far East as Yunnan in southern parts of China.

Oleander grows well in warm subtropical regions, where it is extensively used as an ornamental plant in landscapes, parks, and along roadsides. Over 400 cultivars have been named, with several additional flower colours not found in wild plants having been selected, including red, purple, pink and orange; white and a variety of pinks are the most common. Many cultivars also have double flowers. Oleander is one of the most poisonous of commonly grown garden plants, and can be very toxic if ingested in sufficient quantity. Despite this and a lack of any proven benefits, a range of oleander-based treatments are being promoted on the Internet and in some alternative medicine circles.

Local names
English: Oleander.