Lavender

Lavender (botanic name Lavandula) is a genus of 39 species of flowering plants in the mint family, Lamiaceae. It is native to the Old World and is found from Cape Verde and the Canary Islands, southern Europe across to northern and eastern Africa, the Mediterranean, south west Asia to south east India. Many members of the genus are cultivated extensively in temperate climates as ornamental plants for garden and landscape use, and also commercially for the extraction of essential oils.

Cultivation

The most common form in cultivation is the common or English lavender Lavandula angustifolia (formerly named L. officinalis). A wide range of cultivars can be found. Other commonly grown ornamental species are L. stoechas, (Spanish lavender) L. dentata (French lavender), and L. multifida (Egyptian lavender).

Because the cultivated forms are planted in gardens worldwide, they are occasionally found growing wild as garden escapes, well beyond their natural range. Commonly such adventitious establishment is apparently harmless at best, but in some cases Lavandula species have become invasive; for example, in Australia Lavandula stoechas has become a cause for concern; it occurs widely throughout the continent, and has been declared a noxious weed in Victoria since 1920. It also is regarded as a weed in parts of Spain.

Lavenders flourish best in dry, well-drained, sandy or gravelly soils in full sun. All types need little or no fertilizer and good air circulation. In areas of high humidity, root rot due to fungus infection can be a problem. Organic mulches can trap moisture around the plants' bases, encouraging root rot. Gravelly materials such as crushed rocks give better results.

Oil production

Commercially the plant is grown mainly for the production of essential oil of lavender. This has antiseptic and anti-inflammatory properties. These extracts are also used as fragrances for bath products.

English lavender (Lavandula angustifolia) yields an essential oil with sweet overtones, and can be used in balms, salves, perfumes, cosmetics, and topical applications. Lavandin, Lavandula ?intermedia (also known as Dutch lavender), yields a similar essential oil, but with higher levels of terpenes including camphor, which add a sharper overtone to the fragrance.

The lavandins Lavandula ?intermedia are a class of hybrids of L. angustifolia and L. latifolia. The lavandins are widely cultivated for commercial use, since their flowers tend to be bigger than those of English lavender and the plants tend to be easier to harvest, but lavandin oil is regarded by some to be of a lower quality than that of English lavender, with a perfume less sweet.

Culinary use

Flowers yield abundant nectar from which bees make a high-quality honey. Monofloral honey is produced primarily around the Mediterranean, and is marketed worldwide as a premium product. Flowers can be candied and are sometimes used as cake decorations. Lavender flavors baked goods and desserts (it pairs especially well with chocolate), and is also used to make "lavender sugar". Lavender flowers are occasionally blended with black, green, or herbal tea, adding a fresh, relaxing scent and flavor.

Though it has many other traditional uses in southern France, lavender is not used in traditional southern French cooking. It does not appear at all in the best-known compendium of Proven鏰l cooking, J.-B. Reboul's Cuisini鑢e Proven鏰le In the 1970s, a herb blend called herbes de Provence usually including lavender was invented by spice wholesalers, and lavender has more recently become popular in cookery.

Lavender lends a floral and slightly sweet flavor to most dishes, and is sometimes paired with sheep's-milk and goat's-milk cheeses. For most cooking applications the dried buds (also referred to as flowers) are used, though some chefs experiment with the leaves as well. Only the buds contain the essential oil of lavender, from which the scent and flavor of lavender are best derived.

In the United States, both lavender syrup and dried lavender buds are used to make lavender scones and marshmallows.

Medical uses

The essential oil was used in hospitals during World War I.

Lavender is used extensively with herbs and aromatherapy. Infusions are believed to soothe insect bites, burns, and headaches. Bunches of lavender repel insects. In pillows, lavender seeds and flowers aid sleep and relaxation. An infusion of flowerheads added to a cup of boiling water is used to sooth and relax at bedtime[citation needed]. Lavender oil (or extract of Lavender) is used to treat acne when diluted 1:10 with water, rosewater, or witch hazel; it also treats skin burns and inflammatory conditions.

A recent clinical study investigated anxiolytic effects and influence on sleep quality. Lavender oil with a high percentage of linalool and linalyl acetate, in the form of capsules, was generally well tolerated. It showed meaningful efficacy in alleviating anxiety and related sleep disturbances.

Health precautions

Lavender oil can be a powerful allergen, and it is also recommended that it should not be ingested during pregnancy and breastfeeding.

In vitro, lavender oil is cytotoxic. It increases photosensitivity as well. Lavender oil is cytotoxic to human skin cells in vitro (endothelial cells and fibroblasts) at a concentration of 0.25%. Linalool, a component of lavender oil, may be its active component. Aqueous extracts reduced mitotic index, but induced chromosomal aberrations and mitotic aberrations in comparison with control, significantly. Aqueous extracts induced breaks, stickiness, pole deviations and micronuclei. These effects were related to extract concentrations.

However, according to a 2005 study "although it was recently reported that lavender oil, and its major constituent linalyl acetate, are toxic to human skin cells in vitro, contact dermatitis to lavender oil appears to occur at only a very low frequency. The relevance of this in vitro toxicity to dermatological application of lavender oils remains unclear."

In terms of phototoxicity, a 2007 investigative report from European researchers stated that, "Lavender oil and sandalwood oil did not induce photohaemolysis in our test system. However, a few reports on photosensitivity reactions due to these substances have been published, e.g. one patient with persistent light reaction and a positive photo-patch test to sandalwood oil."

In 2007, a study was published in the New England Journal of Medicine which indicated that studies in human cell lines indicated that both lavender oil and tea tree oil had estrogenic and antiandrogenic activities. They concluded that repeated topical exposure to lavender and tea tree oils probably caused prepubertal gynaecomastia in some boys. The Aromatherapy Trade Council of the UK has issued a rebuttal, and it is also disputed by the Australian Tea Tree Association, a group that promotes the interests of Australian tea tree industry.

Other uses

Flower spikes are used for dried flower arrangements. The fragrant, pale purple flowers and flower buds are used in potpourris. Lavender is also used extensively as herbal filler inside sachets used to freshen linens. Dried and sealed in pouches, lavender flowers are placed among stored items of clothing to give a fresh fragrance and to deter moths. Dried lavender flowers have become recently popular for wedding confetti. Lavender is also popular in scented waters and sachets.