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Acoraceae FAMILY

Acorus calamus calamus

Acorus calamus calamus

Edibility
3/5
Medicinal
4/5

Safety & Hazards

The plant is found in three distinct forms, one diploid, one triploid and one tetraploid. This record is for the triploid form, the essential oil of which has been shown to contain a small amount of the compound beta-asarone. Research has shown that beta-asarone has potential carcinogenic and hepatotoxic effects upon the body if used in quantity, though it is present in too small a quantity to be of harm when the root is consumed[1]. The essential oil (like all essential oils), if ingested in its pure form, can be toxic in all but very small quantities[2, 3]. In practice, when the whole root is used medicinally, the plant has shown itself to be safe and beneficial to use - as is shown by the wide medicinal use of the plant in Asia, where they use this form which is rich in beta-asarone[3, 1].

Cultivation Details

HabitPerennial
Growth—

Sweet flag is a widespread plant that can be found from the cold temperate zone right through to the tropics. It is tolerant of a wide range of environmental conditions, though it grows best in areas where annual daytime temperatures are within the range 18 - 26°c, and can tolerate 4 - 30°c[4]. When dormant, the plant can survive temperatures down to about -25°c[5, 4]. It prefers a mean annual rainfall in the range 700 - 2,000mm, but tolerates 430 - 4,200mm[4]. Succeeds in a wide range of soils, requiring a position in shallow water or in a very moist loamy soil[6]. Requires a sunny position[6]. Prefers a pH in the range 5.5 to 6.5, tolerating 5 - 7.5[4]. The plant never sets seed unless it is growing in water[7]. It can spread quite freely at the roots and soon becomes established. Acorus calamus has diploid, triploid, and tetraploid forms. The different cytotypes show a great morphological variability and also a large variation in the chemical composition of the essential oils from the rhizome and leaves. As a result, they have been considered as representing species or varieties: Acorus calamus var. Calamus (or A. Calamus var. Vulgaris) for the triploids, A. Calamus var. Americanus for the diploids, and A. Calamus var. Angustus for the tetraploids. Acorus calamus is considered in this treatment as a variable species, and infraspecific taxa are not recognized because there is an overlap in the width of the leaves, from 0.8 cm to 1.5 or 2 cm, also from Asiatic collections from different geographical regions, and furthermore the length of the spadices is variable. It can be observed that several collections from Asia have somewhat narrower leaves, ca. 1 cm wide; but there are also broader ones, and there is a continuous series.

Propagation

Seed - best sown in a cold frame as soon as it is ripe. Stand the pot in about 3cm of water. Pot up young seedlings as soon as they are large enough to handle, keep them wet by standing the pots in shallow water and overwinter for the first year in a greenhouse or cold frame. Seed is rarely produced in cool temperate areas[7, 8]. Division in spring just before growth starts[9]. Very easy, it can be carried out successfully at any time in the growing season and can be planted direct into its permanent positions[PFAF]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Acorus+calamus+calamus>

Pollinators

Insects

References

  1. [1]The Sweetness and Bitterness of Sweet Flag (Acorus calamus L.) - A Review — Mythili Avadhani MN et al · 2013 · ISBN 0975-8585 ↩︎A review of the literature regarding the medicinal and other uses of Acorus calamus.
  2. [2]Encyclopaedia of Herbs and their Uses. — Bown. D. · Dorling Kindersley, London. · 1995 · ISBN 0-7513-020-31 ↩︎A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant.
  3. [3]The Encyclopedia of Medicinal Plants — Chevallier. A. · Dorling Kindersley. London · 1996 · ISBN 9-780751-303148 ↩︎An excellent guide to over 500 of the more well known medicinal herbs from around the world.
  4. [4]Ecocrop — http://ecocrop.fao.org/ecocrop/srv/en/home ↩︎Basic information on a wide range of useful plants, plus details of environmental needs where available.
  5. [5]Perennials. Volumes 1 and 2. — Phillips. R. & Rix. M. · Pan Books · 1991 · ISBN 0-330-30936-9 ↩︎Photographs of over 3,000 species and cultivars of ornamental plants together with brief cultivation notes, details of habitat etc.
  6. [6]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  7. [7]A Modern Herbal. — Grieve. · Penguin · 1984 · ISBN 0-14-046-440-9 ↩︎Not so modern (1930's?) but lots of information, mainly temperate plants.
  8. [8]Flora of the British Isles. — Clapham, Tutin and Warburg. · Cambridge University Press · 1962 · ISBN - ↩︎A very comprehensive flora, the standard reference book but it has no pictures.
  9. [9]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  10. [10]Plant Resources of Southeast Asia — http://proseanet.org/ ↩︎Lots of information on the uses of the plants of SE Asia.
  11. [11]Flowers of Europe - A Field Guide. — Polunin. O. · Oxford University Press · 1969 · ISBN 0192176218 ↩︎An excellent and well illustrated pocket guide for those with very large pockets. Also gives some details on plant uses.
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  16. [16]A Field Guide to N. American Edible Wild Plants. — Elias. T. and Dykeman. P. · Van Nostrand Reinhold · 1982 · ISBN 0442222009 ↩︎Very readable.
  17. [17]The Useful Plants of Great Britain. — Johnson. C. P. ↩︎Written about a hundred years ago, but still a very good guide to the useful plants of Britain.
  18. [18]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
  19. [19]The Dictionary of Useful Plants. — Coon. N. · Rodale Press · 1975 · ISBN 0-87857-090-x ↩︎Interesting reading but short on detail.
  20. [20]Famine Foods listed in the Chiu-Huang Pen-ts'ao. — Reid. B. E. · Southern Materials Centre; Taipei · 1977 · ISBN - ↩︎A translation of an ancient Chinese book on edible wild foods. Fascinating.
  21. [21]Narcotic Plants — Emboden. W. · Studio Vista · 1979 · ISBN 0-289-70864-8 ↩︎A lot of details about the history, chemistry and use of narcotic plants, including hallucinogens, stimulants, inebriants and hypnotics.
  22. [22]A Dictionary of Plants Used by Man. — Usher. G. · Constable · 1974 · ISBN 0094579202 ↩︎Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.
  23. [23]Plants for Man. — Schery. R. W. ↩︎Fairly readable but not very comprehensive. Deals with plants from around the world.
  24. [24]Plants Consumed by Man. — Brouk. B. · Academic Press · 1975 · ISBN 0-12-136450-x ↩︎Readable but not very comprehensive.
  25. [25]Plants for Human Consumption. — Kunkel. G. · Koeltz Scientific Books · 1984 · ISBN 3874292169 ↩︎An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
  26. [26]Plants and People of Nepal — Manandhar. N. P. · Timber Press. Oregon. · 2002 · ISBN 0-88192-527-6 ↩︎Excellent book, covering over 1,500 species of useful plants from Nepal together with information on the geography and peoples of Nepal. Good descriptions of the plants with terse notes on their uses.
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  28. [28]Encyclopaedia of Medicinal Plants. — Chiej. R. · MacDonald · 1984 · ISBN 0-356-10541-5 ↩︎Covers plants growing in Europe. Also gives other interesting information on the plants. Good photographs.
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  32. [32]The Dictionary of Modern Herbalism. — Mills. S. Y. ↩︎An excellent small herbal.
  33. [33]Earth Medicine, Earth Food. — Weiner. M. A. · Ballantine Books · 1980 · ISBN 0-449-90589-6 ↩︎A nice book to read though it is difficult to look up individual plants since the book is divided into separate sections dealing with the different medicinal uses plus a section on edible plants. Common names are used instead of botanical.
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  41. [41]A - Z of Companion Planting. — Allardice.P. · Cassell Publishers Ltd. · 1993 · ISBN 0-304-34324-2 ↩︎A well produced and very readable book.
  42. [PFAF]Plants for a Future — pfaf.org ↩︎