names: bee balm, melissa, balm, common balm
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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%.
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.
1992: The New Zealand nursery register 1992/93. Reference Publishing Co.
Auckland, New Zealand.
C. (ed. Lord, T) 1991: The plant finder 1991/92 Edition. Headmain Ltd.
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)
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.
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.
& 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.
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.
of value-added products such as tea bags, or perhaps, flavour extracts
has more potential.
J.A. 1985: Culinary herbs, a pot-pourri. Trado-Medic Books, Conch Magazine
Ltd, New York, USA.
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
A.Y. 1980: Encyclopedia of common natural ingredients in food, drugs and
cosmetics. Wiley, New York, USA.
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