Backhousia citriodora (Lemon myrtle)
Species: B. citriodora
Binomial name: Backhousia citriodora
Common names: Lemon myrtle, Lemon scented myrtle, Lemon scented ironwood, Sweet verbena tree, Sweet verbena myrtle, Lemon scented verbena, Lemon scented backhousia
Backhousia citriodora is a flowering shrub that is endemic to subtropical rainforests of central and south-eastern Queensland, Australia. It can reach 20 m in height, but is often smaller. The leaves are evergreen, opposite, lanceolate, 5–12 cm long and 1.5–2.5 cm broad, glossy green, with an irregular margin. The flowers are creamy-white, 5–7 mm diameter, produced in clusters at the ends of the branches from summer through to autumn, after petal fall the calyx is persistent.
Lemon myrtle was given the botanical name Backhousia citriodora in 1853 after the English botanist, James Backhouse.
The common name reflects the strong lemon smell of the crushed leaves. "Lemon scented myrtle" was the primary common name until the shortened trade name, "lemon myrtle", was created by the native foods industry to market the leaf for culinary use. Lemon myrtle is now the more common name for the plant and its products.
Lemon myrtle is sometimes confused with "lemon ironbark", which is Eucalyptus staigeriana.
B.citriodora has two essential oil chemotypes: The citral chemotype is more prevalent and is cultivated in Australia for flavouring and essential oil. Citral as an isolate in steam distilled lemon myrtle oil is typically 90–98%, and oil yield 1–3% from fresh leaf. It is the highest natural source of citral. The citronellal chemotype is uncommon and can be used as an insect repellent.
Indigenous Australians have long used lemon myrtle, both in cuisine and as a healing plant.