Lemon balm

An illustration of Melissa officinalis from Flora von Deutschland Österreich und der Schweiz (1885)

Lemon balm (Melissa officinalis) is a perennial herbaceous plant in the mint family Lamiaceae,[1] and native to south-central Europe, the Mediterranean Basin, Iran, and Central Asia, but now naturalized in the Americas and elsewhere.[5] The second name, officinalis (Latin, 'of the shop'), originates from the use of the herb by apothecaries, who sold herbal remedies directly to their customers.[6]

Lemon balm plants grow bushy and upright to a maximum height of 100 cm (39 in). The heart-shaped leaves are 2–8 centimetres (0.79–3.15 in) long, and have a rough, veined surface. They are soft and hairy with scalloped edges, and have a mild lemon scent. During summer, small white or pale pink flowers appear. The plants live for ten years; the crop plant is replaced after five years to allow the ground to rejuvenate.[7]

The use of lemon balm can be dated to over 2000 years ago through the Greeks and the Romans. It is mentioned by the Greek polymath Theophrastus in his Historia Plantarum, written in c.300 BC,[8] as "bee-leaf" (μελισσόφυλλον).[9] Lemon balm was formally introduced into Europe in the 7th century, from which its use and domestication spread.[8] Its use in the Middle Ages is noted by herbalists, writers, philosophers, and scientists.

Lemon balm was a favourite plant of the Tudors, who scattered the leaves across their floors.[10] It was in the herbal garden of the English botanist John Gerard in the 1590s,[11] who considered it especially good for feeding and attracting honeybees.[12] Especially cultivated for honey production, according to the authors Janet Dampney and Elizabeth Pomeroy, "bees were thought never to leave a garden in which it was grown".[10] It was introduced to North America by the first colonists from Europe; it was cultivated in the Gardens of Monticello, designed by the American statesman Thomas Jefferson.[13]

The English botanist Nicholas Culpeper considered lemon balm to be ruled by the planet Jupiter in Cancer, and suggested it to be used for "weak stomachs", to cause the heart to become "merry", to help digestion, to open "obstructions of the brain", and to expel "melancholy vapors" from the heart and arteries.[14]

In traditional Austrian medicine, M. officinalis leaves have been prescribed as a herbal tea, or as an external application in the form of an essential oil.[15]

Lemon balm is the main ingredient of carmelite water, which is sold in German pharmacies.[16]

The plant is grown and sold as an ornamental plant, and for attracting bees. The essential oil is used as a perfume ingredient.[17] It is used in toothpaste.[18]

Lemon balm is used as a flavouring[17] in ice cream and herbal teas, often in combination with other herbs such as spearmint. The leaves are not dried when used for tea. It is a common addition to peppermint tea, mostly because of its complementing flavor. Lemon balm is also used with fruit dishes or candies. It can be used in fish dishes and is the main ingredient in lemon balm pesto.[19]^: 15–16 Its flavour comes from geraniol (3–40%), neral (3–35%), geranial (4–85%) (both isomers of citral), (E)-caryophyllene (0–14%), and citronellal (1–44%).[20] It is also one of the ingredients in Spreewald gherkins.[21]

A bumblebee feeding on a lemon balm flower

Melissa officinalis is native to Europe, central Asia and Iran, but is now naturalized around the world.[3][19] It grows easily from seed, preferring rich, moist soil.[22]

Lemon balm seeds require light and a minimum temperature of 20 °C (68 °F) to germinate. The plant grows in clumps and spreads vegetatively (a new plant can grow from a fragment of the parent plant), as well as by seed. In mild temperate zones, the plant stems die off at the start of the winter, but shoot up again in spring. Lemon balm grows vigorously.[23]

As of 1992, Hungary, Egypt, and Italy are the major producing countries of lemon balm.[4] The leaves are harvested by hand in June and August in the northern hemisphere, on a day when the weather is dry, to prevent the crop from turning black if damp.[7]

The cultivars of M. officinalis include:

• M. officinalis 'Citronella'
• M. officinalis 'Lemonella'
• M. officinalis 'Quedlinburger'
• M. officinalis 'Lime'
• M. officinalis 'Mandarina'
• M. officinalis 'Variegata'
• M. officinalis 'Aurea'
• M. officinalis 'Quedlinburger Niederliegende', an improved variety bred for high essential oil content.

Essential oil production

Ireland is a major producer of lemon balm essential oil, which has a pale yellow colour and a lemon scent.[4] The essential oil is commonly co-distilled with lemon oil, citronella oil or other essential oils.[24] Yields are low; 0.014% for fresh leaves and 0.112% for dried leaves.[4]

The plant seen in visible light, ultraviolet light and infrared

Lemon balm contains eugenol, tannins, and terpenes.[25]