Nerium oleander (oleander)
Nerium oleander, commonly known as oleander, is a highly toxic plant that has been cultivated since ancient times.
Nerium oleander (Photo: Armin Jagel, Bochumer Botanischer Verein, Germany)
Found mostly in seasonally dry rocky watercourses, in full sun.
All parts of the plant are extremely toxic if eaten; contact with the sap may cause dermatitis; avoid inhaling smoke if burning plants.
About this Species
Nerium oleander is a highly toxic ornamental shrub widely cultivated in the Mediterranean. It has been grown since ancient times and features in many of the Roman wall paintings in Pompeii.
Alexander the Great in his military campaigns is said to have lost men as a result of eating meat skewered on the highly poisonous Nerium twigs.
Geography and distribution
Native to the Mediterranean region, Iran, the Indian subcontinent and southern China.
Nerium oleander is an evergreen shrub (or small tree) that grows to approximately 6 m. A sticky latex is exuded if the stem is cut. Leaves are usually in groups of three and narrowly lanceolate. The flowers are tubular with five lobes, red or pink in the wild, but in addition may be white, cream, yellow or purple in cultivars, and double forms have also been selected. Some are scented. The fruit is composed of a pair of follicles that split along one side to release the seeds. The seeds are oblong, with a plume of hairs at one end.
Threats and conservation
Oleander is not threatened globally. Plants are threatened in the wild in some areas through excessive development, but will persist in cultivation.
Nerium oleander is widely cultivated as an ornamental shrub or as an informal hedge in warm-temperate and dry subtropical regions, and as a plant for the conservatory in cooler climates. It is highly poisonous to humans, pets, livestock and birds due to the presence of cardiac glycosides, mainly oleandrin. Ingestion causes nausea, vomiting, cardiac arrhythmias, hypotension (low blood pressure) and death. Its sap has been used as rat poison.
Oleandrin is used for treating cardiac conditions in patients who cannot tolerate digitalis. In traditional medicine, the leaves have been used for a variety of medicinal purposes, including the treatment of heart diseases, as a diuretic, antibacterial, and against snake-bite. The leaves also show insecticidal activity against sugarcane mite and citrus leafminer. The roots have been used externally in traditional medicine for treating cancer, ulcers and leprosy. In Western Sahara the ash from Nerium oleander is mixed with saltpetre to make gunpowder.
Millennium Seed Bank: Seed storage
Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.
Number of seed collections stored in the Millennium Seed Bank: Two
Seed storage behaviour: Orthodox (the seeds of this plant survive being dried without significantly reducing their viability, and are therefore amenable to long-term frozen storage such as at the MSB)
Germination testing: Successful
Composition values: Oil content 17.4-29.4%, Protein 30%
A tender plant, Nerium oleander can survive light frosts, but show signs of frost damage. It is a common landscape plant in tropical and subtropical climates and grows in a wide range of soils. It can withstand drought and salt spray, being widely used in coastal areas, and reacts well to full sun or partial shade. The species can be propagated by semi-ripened cuttings in summer or seeds. Hard pruning helps to maintain its shape.
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Huxley, A., Griffiths, M. & Levy, M. (eds) (1992). The New Royal Horticultural Society Dictionary of Gardening, 4 vols. Macmillan, London.
Bruneton, J. (1999). Toxic Plants Dangerous to Humans and Animals. Lavoisier Publishing, Paris.
Pagen, F.J.J. (1987). Series of revisions of Apocynaceae. Part XX: Oleanders. Nerium L. and the Oleander Cultivars. Agricultural University, Wageningen Papers 87-2: 1-113.
Mabberley, D.J. (2008). Mabberley’s Plant-book: A Portable Dictionary of Plants, their Classification and Uses. 3rd Ed. Cambridge University Press.
National Institute of Science Communication and Information Resources (CSIR) (2003). The wealth of India: a dictionary of Indian raw materials and industrial products. First Supplement Series (Raw Materials), Vol. 4: J-Q. CSIR, New Delhi.
Kew Science Editor: David Goyder
Kew contributors: Sustainable Uses Group
Copy editing: Kew Publishing
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