Home page Who we areWhat we doProductsOpportunities
SectorsPopular pubsSci. PubsServicesProducts
Crop and Food ResearchSearch
 
   

Lemon Balm - Melissa officinalis

Malcolm Douglas : DouglasM@crop.cri.nz
Redbank Research Station
A printed copy with photos is available. Updated: June, 1993

23K jpg lemon balm

Other names: bee balm, melissa, balm, common balm

Lemon balm is a vigorous perennial herb with a pleasant lemon scent that belongs to the Labiatae family. It grows up to 1 m tall. Inconspicuous white flowers appear in the axils of the leaves in mid-summer. Leaves are usually hairless and bright green. There are three subspecies of lemon balm that vary in the intensity of their scent. One subspecies found growing wild in the Coromandel has a fruit-mint scent instead of the traditional lemon. Lemon balm is native to southern Europe, but it has naturalised widely throughout Europe and elsewhere, including New Zealand. 

Uses

Lemon balm is a traditional European medicinal herb, but its use in cooking and garnishing, and as a refreshing tea is increasing. It is considered to have carminative and antispasmodic activity and is used to treat all sorts of ailments including insomnia, cramps, headache and toothache. It has a reputation as a cure-all, and is often used in herbal mixtures to help disguise the taste of other, less pleasant herbs.

An essential oil, called melissa oil, can be extracted from lemon balm, but yields are very low. The oil is usually heavily adulterated with other lemon-scented oils such as lemongrass and lemon oil. Lemon balm extracts and oil are used to flavour alcoholic and non-alcoholic beverages, confectionary and processed food products. The essential oil is sometimes used as an ingredient in perfumes.

Hot-water extracts (equivalent to a herb tea) of lemon balm have strong anti-viral activity against a range of virus infections including mumps. The essential oil has been reported to have antibacterial and antispasmodic activity in vitro

Growing environment

Lemon balm grows easily in most situations, preferring a friable loam soil with good drainage. It will tolerate partial shade and damper soils than most other herbs, but will not thrive in waterlogged or very dry conditions. It has been suggested that lemon balm develops better scent and flavour when grown in harder conditions, and situations that promote lush growth produce a foliage low in aroma. However, production of dried herb material responds very strongly to good irrigation and fertiliser management. The relationship between herb yield and quality has yet to be assessed in Crop & Food Research trials. 

Agronomy

Lemon balm can be established from seed, or by cuttings or plant division. Some variability occurs between plants grown from seed, but this is the method usually used to establish the crop overseas. Seed should be sown in a nursery bed or cell trays and later transplanted to the field. Lemon balm self-seeds easily in the field, so seed with a high germination percentage may be established directly in the field.

Lemon balm grows easily from cuttings or rooted layers at any time of the year. The plants layer naturally in the field and quickly cover the ground surface.

Lemon balm plants can tolerate some traffic, so it may be possible to establish the crop on a broad scale. Alternatively, the crop can be planted in beds approximately 1.5 m wide. Width of beds should be designed so that vehicles can straddle the crop without damaging it during mechanised weed control, harvesting procedures etc. A spacing of 30 cm between plants is recommended. Plants will spread quickly and complete ground cover should be achieved at the end of the first season.

Lemon balm tolerates a range of herbicides, although questions of residues on herb material, particularly for the export market, need to be addressed. There is a trend towards "spray-free" requirements for herbs used in herbal tea preparations - the major use of lemon balm. Weed control in lemon balm is more time consuming without the use of herbicides. Much hand weeding would be needed to maintain a clean crop, and mulches such as sawdust and straw would be helpful. In Germany, the crop is replanted every two or three years and rotated with other crops to aid in weed control.

Some herbicides showing potential for selective weed control in Crop & Food Research trials include Sinbar, Stomp and winter applications of Preeglone. Although non-chemical weed control may ultimately be desirable, it may not be feasible to grow lemon balm on a large scale in New Zealand without some herbicide assistance.

Lemon balm can be attacked by a variety of pests and diseases. European red mite and two-spotted mite cause bronzing of young growth and can severely reduce production. Mites were a particular problem on lemon balm grown in Crop & Food Research trials in Central Otago. Various aphids have also been observed on the crop, but damage has not been severe. Lemon balm has large, soft leaves and is attacked by a range of leaf diseases including Septoria leaf spot. Poorly-drained soil conditions can predispose the crop to attack from root and crown rots. Good crop management and choice of site can minimise pest and disease problems.

Soil tests should be carried out to determine fertiliser requirements. A basal fertiliser application containing nitrogen, phosphorus, sulphur and potassium should be applied annually. Leafy herb crops, such as lemon balm, also respond well to additional applications of nitrogen during the growing season, usually applied after harvest to boost new shoot growth. Potassium applications at this time may also be beneficial. 

Processing and quality

Lemon balm herb should be dried artificially to allow better control of product quality. A forced air-flow drier would be suitable. Lemon balm should be dried at temperatures less than 40°C to reduce loss of flavour, and to maintain a good green colour.

The dried material must then be processed to remove leaf material from stems and sieved to remove dust and produce a uniform product. Leaf removal from stems by rubbing is aided by drying the crop to the point where leaf material is brittle, but stems remain supple. Rubbing should be carried out as soon as this stage has been reached, as leaves soon regain some elasticity and efficient removal becomes difficult.

There are no International Standards detailing quality requirements for dried lemon balm. Most material is used in the herbal tea market, and individual companies use their own in-house standards to gauge quality. 

Yields

Production of dried lemon balm herb at different locations in New Zealand is given in Table 1. Good horticultural management, irrigation, fertiliser and weedcontrol were used in this study. Recovery of dried leaf material after processing depends on the stalkiness of the material. The percentage of dried rubbed herb obtained from whole dried herb was around 50-70%.

Crops of lemon balm are rarely grown for essential oil production. Yields of essential oil are very low, usually less than 0.05% (0.5 ml oil/kg herb). The oil can be extracted from fresh or dried flowering tops of the herb. Trials in Central Otago yielded 0.019% of essential oil from fresh herb material. Solvent extraction of frozen herb yielded 0.18% of a waxy, green concrete, approximately 10 times the yield from steam distillation. 

Seed sources

Anon, 1992: The New Zealand nursery register 1992/93. Reference Publishing Co. Auckland, New Zealand.

Philip, C. (ed. Lord, T) 1991: The plant finder 1991/92 Edition. Headmain Ltd. UK.

Isaacson, R.T. 1989: Andersen Horticultural Library Library's Source List of Plants and Seeds. Andersen Horticultural Library, University of Minnesota, USA.
Table 1: Indicative yields of lemon balm grown at six sites in New Zealand. Production of unprocessed dried herb (kg/ha)
Site Year of establishment Established crop
Hamilton 1010 9830
Hastings 870 5930
Blenheim not harvested 13,010
Clyde 2710 9060
Mosgiel not harvested 8560
Invercargill 1010 7360

Markets

New Zealand's small requirements for lemon balm are currently met by imported material. Some of this herb is then re-exported in herbal tea bags. A certain amount of import substitution could be expected, but the bulk of New Zealand production is destined for the export market. Most bulk herbs are produced in countries with low labour costs, so the challenge for New Zealand growers is to produce crops of superior quality at a competitive price.

It is very difficult to determine the size of the world market for herbs such as lemon balm, as specific trade statistics are not available. European countries such as Germany, Italy and France cultivate lemon balm herb. Other producers include the Eastern bloc and Egypt. Hamburg, Germany, is regarded as a trade centre in medicinal herbs for the EC. At present, ample supplies of lemon balm herb are available on the German market and wholesale prices range from NZ$2.00 to 2.50/kg dried herb.

Future prospects

Crop & Food Research is continuing research on lemon balm production in New Zealand. The crop is being grown at several sites nationwide to assess the effect of environment on the production and quality of dried herb. Drying and processing methods are also being evaluated.

The market for lemon balm is more akin to that for medicinal herbs rather than the traditional culinary herbs. Trade sources suggest that although the market is relatively small at present, it is experiencing steadygrowth as people seek alternatives for healthy living. Europe is a major consumer of medicinal herb products. Production of alternative crops in the EC is being promoted to help alleviate the massive surpluses of traditional crop production. Therefore, prices tend to be low. It is unlikely that New Zealand producers could compete effectively in the production of bulk, dried lemon balm herb because of high transport costs.

Production of value-added products such as tea bags, or perhaps, flavour extracts has more potential.

Further reading

Duke, J.A. 1985: Culinary herbs, a pot-pourri. Trado-Medic Books, Conch Magazine Ltd, New York, USA.

Guenther, E. 1949: Oil of balm. In: The essential oils. Vol. 3: Individual essential oils of the plant families Rutaceae and Labiatae. Kreiger, Florida, USA. pp. 395-399

Leung, A.Y. 1980: Encyclopedia of common natural ingredients in food, drugs and cosmetics. Wiley, New York, USA. 


Printed copies of this page

This page is available in printed form with colour photo at a cost of:
New Zealand - NZ$3.00;
Australia - A$3.00; 
Everywhere else US$3.00 
Click to order


 
 
 
Back to top

While every care has been taken when preparing this document, no liability will be accepted by the New Zealand Institute for Crop & Food Research Limited for any loss or damage suffered as a result of applying the information contained in this document. Copyright © 1999 The New Zealand Institute for Crop & Food Research Limited, Private Bag 4704, Christchurch, New Zealand.