Cultivated trees are often cut back to 6 feet so the flowers can easily be reached. Harvesting takes place year round, with each flower hand-picked only when its maturity is signaled by a red tinge at its base. The flowers are picked very early in the morning and distilled immediately. Ylang ylang was native to southeast Asia but is now cultivated in other tropical or subtropical areas, particularly on the island of Nosy Bé and the Comoro Islands, north of Madagascar, and Réunion, to the east, which approaching sailors called “the perfumed isles.” The essential oil has a reputation as an aphrodisiac and has long been a component in some of the most expensive perfumes. Some flowers are processed by fractional steam distillation, resulting in oils of different densities, classed as grades: extra, first, second, and third. Extra grade is produced after two hours of distillation, whereas grade three is the result of up to 20 hours of distillation. The fragrance intensity is strongest in the extra oil, reducing with each grade to third. Complete essential oil results from a single distillation process, which can take up to 10 hours. The essential oil of cananga is produced, usually in Asia, from a tree of the same genus and species as ylang ylang but a different variety. It has an aroma similar to ylang ylang but not as floral, but it is sometimes sold as ylang ylang.