Common name: Aniseed myrtle

Aniseed myrtle is an essential-oil yielding tree originating in Australia and occurs there on the east coast of the continent, in a small area of subtropical forest in northern New South Wales, in the vicinity of Nambucca, Bellingen and Dorrigo townships.

It may grow into a large tree in its natural forest habitats, reaching heights of up to 50 m (164 ft) or more. On open sites, it is more typically 6 to 12 m (20 to 40 ft) tall and develops a short, straight trunk supporting a densely leafy rounded or pyramidal crown. The bark is grey or grey-brown, corky and with shallow vertical fissures.

Leaves lance-shaped, 6 to 12 cm (2.4 to 4.8 in) long, wavy on the margins and arranged in pairs along the branches. They emerge crimson-red, with age become dark glossy green and give off a sweet, aniseed aroma when crushed.

The flowers are small, white, four- to five-petaled with long filaments, sweetly fragrant and in branched clusters at the ends of the branches. They come into bloom in spring and are followed by small funnel-shaped seed capsules that become dry and brown when mature.

Use

The leaves yield on steam distillation an aniseed essential oil traded as 'Aniseed Myrtle Oil'. It is a clear, colourless to pale yellow, free-flowing oil with a sweet aniseed aroma, closely similar to, and a good substitute for, 'Anise oil' from Anise (Pimpinella anisum) and 'Star anise oil' from Star Anise (Illicium verum). Aniseed Myrtle leaves yield from 1.3 to 2.0% of essential oil.

The unique fragrance and flavour properties of aniseed-type essential oils are derived from anethole, an aromatic, volatile compound present in some plants. Anethole constitutes over 90% of Aniseed myrtle oil, about the same for Anise oil, but for Star anise oil it is less, around 80%.

Anise-type oils are widely used in the food, beverage and pharmaceutical industries, to give flavour and aroma to baked goods, dairy desserts, teas, liquors, such as 'Anisette de Bordeaux' and 'Pastis', oral hygiene products, including toothpaste and mouthwashes and medicines, such as cough medicines. It is also used in the cosmetic industry as a fragrance in perfumes, men's colognes and skin-care formulations.

Aniseed myrtle oil has also been shown to have anti-fungal and anti-microbial properties, holding promise for a variety of applications, including use as a natural preservative in foods.

The leaves are used in their natural form as a culinary herb, either fresh or dried, whole or ground into a powder. And like the essential oil, they are used to impart their aniseed flavour to dishes, sauces and beverages.

It produces a reddish-brown wood with good natural resistance to rot, decay and wood-boring insects, but the trees are not usually logged and may be legally protected, due to its restricted distribution and scattered occurrence at only a few locations.

Health use

Aniseed myrtle oil is used in aromatherapy for its calming and relaxing effects.

Climate

Grows naturally in moderately humid warm-temperate to subtropical climates, generally in frost-free areas with annual lows of 10 to 16°C, annual highs of 18 to 26°C, annual rainfall of 1400 to 3000 mm and a dry season of 3 months or less.

Growing

New plants are grown from cuttings, as seed are not always readily available. Performs best on deep, rich, free-draining clay and loam soils of a moderately acid to neutral nature, generally with a pH of 5.5 to 7.0, and on sites with full to partial sun exposure.

Problem features

There does not appear to be any record of it anywhere as a weed, and due to its shy seeding habit is unlikely to become a weed problem.

Books

• Floyd, A. G. 1979, N.S.W. rainforest trees, 2nd. ed., Forestry Commission of NSW, Sydney, Australia

• Preedy, V. R., (editor.) 2015, Essential oils in food preservation, flavor and safety, Elsevier Ltd, Amsterdam, The Netherlands

• Sultanbawa, Y. & Sultanbawa, F. 2016, Australian native plants : cultivation and uses in alternative medicine and the food industry, CRC Press, Boca Raton, Florida