Oleander belongs to the Apocynaceae family. It is the only species in the genus Nerium. The main botanical synonyms for this species are Nerium indicum, Nerium latifolium, Nerium lauriforme and Oleander indica. Its natural range extends from the Mediterranean basin (Portugal, Spain, southern France, Italy, the Balkans, North Africa) to the Near East, Iran, Pakistan, the foothills of the Himalayas and Burma, where it colonises the beds of torrents, wadis and alluvial valleys, often close to a water source, but subject to long periods of drought.
The cultivar ‘Isle of Capri’ is a horticultural selection introduced around 1963 by the Californian nursery Monrovia Nursery; some authors consider it to be the same as a clone known as ‘I. Lovenberg’. It is reputed to be one of the most reliable single yellow oleanders. The shrub has an upright, bushy habit, with several greyish trunks starting from the base. At maturity, it forms a bush 2.5 to 3.5 m high and 2 to 3 m wide in open ground, slightly less in a container. Its growth is rather fast in a warm climate. The evergreen foliage is composed of narrow, lanceolate, leathery, dark green leaves, 10 to 15 cm long and 1 to 2 cm wide, arranged in pairs or threes around the stems. The flowering peaks from June to August, and continues until September-October in a Mediterranean climate. The inflorescences are large terminal cymes; each flower, 3 to 4 cm in diameter, with five slightly twisted petals, forms an ivory to creamy yellow star, with a deeper yellow heart more or less streaked with reddish on the corolla tube. As with the type species, the fruits are very narrow, elongated pods, in pairs, which open to release numerous feathery seeds. This cultivar is hardy down to -6/-7°C once mature and in open ground: specimens grown in containers are more sensitive to cold.
It is worth remembering that the oleander, depicted on Roman frescoes in Pompeii, has accompanied Mediterranean landscapes since antiquity, but is also sadly famous for its toxicity: all parts of the plant contain cardiotonic heterosides, which are fatal if ingested.
In the garden, in a favourable climate, ‘Isle of Capri’ expresses its full potential in a very sunny, warm spot, sheltered from cold winds, especially by the sea. Elsewhere, it should be grown in a large pot, to be overwintered frost-free, in a conservatory, cold greenhouse or a bright, unheated room. On a terrace or near a dining area, its evocative name of Isle of Capri transports one to the sun-drenched gardens of the Mediterranean. Its creamy-yellow flowering combines with salmon-pink, red and white tones of other oleanders. In a flowering hedge, you can mix it with hardier varieties such as ‘Papa Gambetta’ with deep salmon-pink flowers, the very floriferous ‘Provence’ with large, fragrant double flowers, the intense red ‘Jannoch’ and a white oleander (Nerium oleander Blanc).
