Backhousia citriodora

2007 Schools Wikipedia Selection. Related subjects: Plants

Lemon myrtle (Backhousia citriodora) is a flowering plant in the family Myrtaceae, native to the semi-temperate rainforests of eastern Australia. It is often mistakenly called "lemon ironbark", which is actually Eucalyptus staigeriana.

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 entire margin. The flowers are creamy-white, 5-7 mm diameter, produced in clusters at the ends of the branches from summer through to autumn.

Lemon myrtle was given the botanical name Backhousia citriodora in 1853 after the English botanist, James Backhouse. The common name reflects the strong sweet lemon smell of the crushed leaves.

Cultivation and uses

Indigenous Australians have long used lemon myrtle, both as an antibiotic and in cuisine. The oil is extremely high in citral content; typically higher than lemongrass. Lemon myrtle essential oil has been shown to possess antimicrobial properties; however it is very toxic to human cells in vitro. When diluted to approximately 1%, absorption through the skin and subsequent damage is thought to be minimal. Use of lemon myrtle oil as a treatment for skin lesions caused by molluscum contagiosum virus (MCV), a disease affecting children and immuno-compromised patients, has been investigated. Nine of sixteen patients who were treated with lemon myrtle oil showed a significant improvement, compared to none in the control group. The oil is a popular ingredient in health care and cleaning products, especially soaps, lotions and shampoos. It is marketed in the capitalized identity of Lemon Myrtle. The majority of commercial lemon myrtle is grown on the north coast of New South Wales, Australia, particularly in the Alstonville region.

The leaves of the plant are also used in cooking, forming one of the more well-known bush tucker foods. It has an extensive range of uses, such as lemon flavouring in pasta, with fish, infused in macadamia or vegetable oils, and made into tea. It can also be used as a lemon replacement in milk-based foods, such as cheescake, lemon flavoured ice-cream and sorbet that would normally curdle due to lemon's citric acid. In World War II the leaves were actually used by the soft drink company Tarax to flavour lemonade. The taste/smell is similar to lemon (hence the name), but 'crisp' and rich, and not acidic. During former US President Bill Clinton's visit to Australia in 1996, lemon myrtle tart was the dessert item at the formal reception hosted by the Australian Government. It is often described as "more lemon than lemon".

The tree is also a popular plant in cultivation and has been successfully grown in cooler districts provided it can be protected from frost when young. In cultivation it rarely exceeds about 5 metres. The principle attraction to gardners is the lemon smell which perfumes both the leaves and flowers of the tree. Lemon myrtle is a hardy plant which tolerates all but the poorest drained soils. It can be slow growing but responds well to slow release fertilisers.