Lemon Myrtle, Backhousia citriodora
The Lemon Myrtle, Backhousia citriodora, also known as Lemon Scented Ironwood, Sweet Verbena Tree, Sweet Verbena Myrtle, or Lemon Scented Verbena, is a flowering plant native to subtropical rainforests of Queensland, Australia. This plant is classified in the family Myrtaceae and genus Backhousia. It can achieve heights as high as 5 yards, but many times it is smaller. The leaves are a glossy evergreen with smooth edges, opposite, lance-shaped, 2-5 inches in length and less than an inch broad. In summer through autumn, the ends of the branches produce clusters of tiny creamy-white flowers. The calyx remains the whole year through even after petals fall away.
Lemon Myrtle was given its common name to suggest the strong aroma of lemon that comes from its crushed leaves. It is sometimes mistaken with “lemon ironbark,” which is Eucalyptus staigeriana.
Lemon Myrtle has two essential oil chemotypes. The most common of these, citral, is cultivated in Australia for flavoring and essential oil. Isolated citral in steam distilled Lemon Myrtle oil is usually 90-98%, and oil yield 1-3% from fresh leaf. It is the purest natural source of citral. The other less prevalent chemotype is citronellal which can be used as an insect repellent. Indigenous Australians have utilized lemon myrtle for many years in both cuisine and as a healing plant. It is regarded as having a “cleaner and sweeter” scent than other similar sources of citral.
In Bushfood cuisine of Australia, Lemon Myrtle is one of the most popular herbs. It has been coined as “Queen of the lemon herbs” for its favored sweetness. Its culinary uses are vast including dried leaf flakes for baking, seasoning of fish and pasta, infusion with other oils, and made into tea. It serves as a unique lemon flavor alternative in milk-based foods without the curdling dilemma associated with lemon fruit acidity.
Antimicrobial properties warrant another valuable benefit of Lemon Myrtle essential oil. However, human cells in vitro reveal that undiluted essential oil is toxic. If diluted to approximately 1%, absorption through the skin and subsequent harm associated with this is determined to be minimal. Treatments using Lemon Myrtle oil for skin lesions caused by molluscum contagiosum virus (MCV), a disease affecting children and immune-deficient patients, have been researched. Results reveal that nine of sixteen patients who received this treatment displayed substantial improvement, compared to none in the control group. The oil is commonly used in health care and cleaning product, particularly soaps, lotions, and shampoos.
Lemon Myrtle is a commercially cultivated ornamental plant. Most commercially produced lemon myrtle is grown in Queensland and the north coast of New South Wales, Australia, but it can be grown in any tropical to warm temperate climate, and may even sustain cooler climates if guarded from frost in early stages of development. In controlled environments, it generally does not exceed 5 yards and typically has a compact canopy. It is a resilient, tolerable plant that can sustain most things but poor drainage. Before the Lemon Myrtle reaches maturity with a strong trunk, it endures a slow, juvenile growth stage as a shrub. Although growth may be slow, it does respond well to slow release fertilizers. To ensure a consistent product and expedite production, cultivators evade this slow shrubby stage by growing cuttings from mature trees. The tree is usually pruned into a shrub for easier maintenance in plantation cultivation. The harvested leaves are dried for leaf spice or distilled for essential oil.