It grows to a maximum height of 1 m (3 ft 3 in). The leaves have a mild lemon scent. During summer, small white flowers full of nectar appear. It is not to be confused with bee balm (genus Monarda), although the white flowers attract bees, hence the genus Melissa (Greek for "honey bee").
The leaves are used as a herb, in teas and also as a flavouring. The plant is used to attract bees for honey production. It is grown as an ornamental plant and for its oil (to use in perfumery). Lemon balm has been cultivated at least since the 16th century.
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.[8]
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 polymathTheophrastus in his Historia Plantarum, written in c.300 BC,[9] as "bee-leaf" (μελισσόφυλλον).[10] Lemon balm was formally introduced into Europe in the 7th century, from which its use and domestication spread.[9] 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.[11] It was in the herbal garden of the English botanistJohn Gerard in the 1590s,[12][page needed] who considered it especially good for feeding and attracting honeybees.[13] 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".[11] 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.[14]
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.[15]
The plant is grown and sold as an ornamental plant, and for attracting bees. The essential oil is used as a perfume ingredient.[18] It is used in toothpaste.[19]
Melissa officinalis is native to Europe, central Asia and Iran, but is now naturalized around the world.[4][20] It grows easily from seed, preferring rich, moist soil.[23]
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.[24]
As of 1992[update], Hungary, Egypt, and Italy are the major producing countries of lemon balm.[5] 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.[8]
Ireland is a major producer of lemon balm essential oil, which has a pale yellow colour and a lemon scent.[5] The essential oil is commonly co-distilled with lemon oil, citronella oil or other essential oils.[26]Yields are low; 0.014% for fresh leaves and 0.112% for dried leaves.[5]
^ abUSDA, NRCS (n.d.). "Melissa officinalis". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 6 July 2015.
Axtell, B.L.; Fairman, R.M. (1992). "Melissa officinalis". Minor Oil Crops. Rome: Food and Agriculture Organization of the United Nations. ISBN978-92-5-103128-5.
Dousti, Mashta (2012). "Evidence-based Traditional Persian Medicine". In Rastogi, Sanjeev; Chiappelli, Francesco; Ramchandani, Manisha Harish; Singh, Ram Harsh (eds.). Evidence-based practice in complementary and alternative medicine : perspectives, protocols, problems, and potential in Ayurveda. Berlin: Springer. ISBN978-3-642-24564-0.