Geography and distribution
Native to the Mediterranean region, Iran, the Indian subcontinent and southern China.
Description
Overview: An evergreen shrub (or small tree) that grows to approximately 6 m. A sticky latex is exuded if the stem is cut.
Leaves: Leaves are usually in groups of three and narrowly lanceolate.
Flowers: The flowers are tubular with five lobes, red or pink in the wild, but may be white, cream, yellow or purple in cultivars, and double forms have also been selected. Some are scented.
Fruits: 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.
Uses Ornamental
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.
Pest control
Oleander 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. The leaves also show insecticidal activity against sugarcane mite and citrus leafminer.
Medicinal
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 roots have been used externally in traditional medicine for treating cancer, ulcers and leprosy.
Other
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.
Two collections of Nerium oleander seeds are held in Kew's Millennium Seed Bank based at Wakehurst in West Sussex.
See Kew's Seed Information Database for further information on Nerium oleander seeds
Cultivation
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.