** 2016 Appeal ** In order to extend our coverage of climate zones, we’ve identified around 700 plants to add to our database. To do this properly and at the same time improve the usability of our website we need extra funds in addition to our regular level of income. more >>

   Bookmark and Share
    By donating to PFAF, you can help support and expand our activities
    Plant Suppliers: Click here for a List
Acorus calamus - L.                
Common Name Sweet Flag - Calamus
Family Araceae
USDA hardiness 4-11
Known Hazards The fresh root can be poisonous[7]. When using the plant medicinally, the isolated essential oil should not be used[165]. The essential oil in the roots of some populations of this plant contains the compound asarone. This has tranquillising and antibiotic activity, but is also potentially toxic and carcinogenic[218, 238]. It seems that these compounds are found in the triploid form of the species (found in Asia) whilst the diploid form (found in N. America and Siberia) is free of the compounds[218, 238]. However, the root (but not the isolated essential oil) has been used in India for thousands of years without reports of cancer which suggests that using the whole herb is completely safe, though more research is needed[254]. Only roots free from or with a low content of beta asarone should be used in human herb therapy. Should be avoided in patients taking monoamine oxidase inhibitor antidepressants as possible side-effects [301].
Habitats Found in moist soils and shallow water in ditches, marshes, river edges and ponds[1, 100, 187, 244].
Range Europe, Asia and N. America. Naturalized in Britain[17].
Edibility Rating  
Medicinal Rating  
Fully Hardy Wet Soil Water Plants Full sun

Bloom Color: Green. Main Bloom Time: Mid summer. Form: Spreading or horizontal, Upright or erect.

Physical Characteristics       
 icon of manicon of flower
Acorus calamus is a PERENNIAL growing to 1 m (3ft 3in) by 1 m (3ft 3in) at a medium rate.
It is hardy to zone (UK) 3 and is not frost tender. It is in flower from May to July, and the seeds ripen from Jul to August. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects.Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It prefers wet soil and can grow in water.

Synonyms Calamus aromaticus
Acorus calamus Sweet Flag - Calamus

Acorus calamus Sweet Flag - Calamus
 Pond; Bog Garden;
Edible Uses                                         
Edible Parts: Leaves;  Root;  Stem.
Edible Uses: Condiment.

The rhizome is candied and made into a sweetmeat[2, 4, 13, 55, 62, 115, 183]. It can be peeled and washed to remove the bitterness and then eaten raw like a fruit[106, 179]. It makes a palatable vegetable when roasted[192] and can also be used as a flavouring[61]. Rich in starch, the root contains about 1% of an essential oil that is used as a food flavouring[1, 13, 57]. The root also contains a bitter glycoside[179]. Some caution is advised, see the notes above on toxicity. The dried and powdered rhizome has a spicy flavour and is used as a substitute for ginger, cinnamon and nutmeg[4, 55, 142, 177, 183]. A pinch of the powdered rhizome is used as a flovouring in tea[272]. The young and tender inflorescence is often eaten by children for its sweetness[4]. Young leaves - cooked[55]. The fresh leaves contain 0.078% oxalic acid[240]. The leaves can be used to flavour custards in the same way as vanilla pods[244]. The inner portion of young stems is eaten raw[62]. It makes a very palatable salad[183].
Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Abortifacient;  Anodyne;  Antirheumatic;  Aphrodisiac;  Aromatic;  Carminative;  Diaphoretic;  Emmenagogue;  Febrifuge;  Hallucinogenic;  Homeopathy;  
Odontalgic;  Sedative;  Stimulant;  Stomachic;  Tonic;  Vermifuge.

Sweet flag has a very long history of medicinal use in many herbal traditions. It is widely employed in modern herbal medicine as an aromatic stimulant and mild tonic[4]. In Ayurveda it is highly valued as a rejuvenator for the brain and nervous system and as a remedy for digestive disorders[254]. However, some care should be taken in its use since some forms of the plant might be carcinogenic - see the notes above on toxicity for more information. The root is anodyne, aphrodisiac, aromatic, carminative, diaphoretic, emmenagogue, expectorant, febrifuge, hallucinogenic, hypotensive, sedative, stimulant, stomachic, mildly tonic and vermifuge[4, 7, 9, 21, 147, 165, 213, 240, 279]. It is used internally in the treatment of digestive complaints, bronchitis, sinusitis etc[238]. It is said to have wonderfully tonic powers of stimulating and normalizing the appetite. In small doses it reduces stomach acidity whilst larger doses increase stomach secretions[254] and it is, therefore, recommended in the treatment of anorexia nervosa[244]. However if the dose is too large it will cause nausea and vomiting[K]. Sweet flag is also used externally to treat skin eruptions, rheumatic pains and neuralgia[238]. An infusion of the root can bring about an abortion[213] whilst chewing the root alleviates toothache[213]. It is a folk remedy for arthritis, cancer, convulsions, diarrhoea, dyspepsia, epilepsy etc. Chewing the root is said to kill the taste for tobacco[218]. Roots 2 - 3 years old are used since older roots tend to become tough and hollow[4]. They are harvested in late autumn or early spring and are dried for later use[4]. The dry root loses 70% of its weight, but has an improved smell and taste[244]. It does, however, deteriorate if stored for too long[244]. Caution is advised on the use of this root, especially in the form of the distilled essential oil, since large doses can cause mild hallucinations[192]. See also the notes above on toxicity. A homeopathic remedy is made from the roots[9]. It is used in the treatment of flatulence, dyspepsia, anorexia and disorders of the gall bladder[9]. Bath oils containing calamus have caused redness of the skin (erythema) and dermatitis, particularly in hypersensitive individuals [301].
Other Uses
Basketry;  Incense;  Insecticide;  Repellent;  Strewing;  Thatching;  Weaving.

The leaves are used in basket making or woven into mats[169]. They have also been used as a thatch for roofs[4]. An essential oil from the rhizome is used in perfumery and as a food flavouring[1, 13, 57]. The oil is contained mainly in the outer skin of the root[245], it has a fragrance reminiscent of patchouli oil[192]. The fresh roots yield about 1.5 - 3.5% essential oil, dried roots about 0.8%[4, 240]. Some plants from Japan have yielded 5% essential oil[4]. The essential oil is also an insect repellent and insecticide[218, 272]. It is effective against houseflies[240]. When added to rice being stored in granaries it has significantly reduced loss caused by insect damage because the oil in the root has sterilized the male rice weevils[244]. An essential oil obtained from the leaves is used in perfumery and for making aromatic vinegars[245]. The leaves and the root have a refreshing scent of cinnamon[245]. All parts of plant can be dried and used to repel insects or to scent linen cupboards[8, 14, 61]. They can also be burnt as an incense[14], whilst the whole plant was formerly used as a strewing herb[4, 14, 115, 238]. The growing plant is said to repel mosquitoes[20, 201].
Cultivation details                                         
Landscape Uses:Container, Ground cover, Massing, Rock garden, Seashore. Prefers growing in shallow water or in a very moist loamy soil[200]. Requires a sunny position[200]. Prefers a pH in the range 5.5 to 7.5. Plants are hardy to about -25°c[187]. The sweet flag has a long history of use as a medicinal and culinary plant. It has been cultivated for this purpose but was more commonly allowed to naturalize and was then harvested from the wild. The plant seldom flowers or sets seed in Britain and never does so unless it is growing in water[4]. It can spread quite freely at the roots however and soon becomes established. Special Features: Attractive foliage, North American native, Edible, Fragrant foliage, Naturalizing, Wetlands plant, Inconspicuous flowers or blooms.
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 Britain[4, 17]. Division in spring just before growth starts[1]. Very easy, it can be carried out successfully at any time in the growing season and can be planted direct into its permanent positions[K].
Related Plants                                         
Latin NameCommon NameEdibility RatingMedicinal Rating
Acorus gramineusGrass-leaved Sweet Rush, Japanese Sweet Flag, Dwarf Sweet Flag33
Iris pseudacorusYellow Flag, Paleyellow iris12
Plant Suppliers: Click here for a List

      You can download this page as a PDF

Expert comment                                         
Botanical References                                         
Links / References                                         

  [K] Ken Fern Notes from observations, tasting etc at Plants For A Future and on field trips.

[1]F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).
[2]Hedrick. U. P. Sturtevant's Edible Plants of the World.
Lots of entries, quite a lot of information in most entries and references.
[4]Grieve. A Modern Herbal.
Not so modern (1930's?) but lots of information, mainly temperate plants.
[7]Chiej. R. Encyclopaedia of Medicinal Plants.
Covers plants growing in Europe. Also gives other interesting information on the plants. Good photographs.
[8]Ceres. Free for All.
Edible wild plants in Britain. Small booklet, nothing special.
[9]Launert. E. Edible and Medicinal Plants.
Covers plants in Europe. a drawing of each plant, quite a bit of interesting information.
[13]Triska. Dr. Hamlyn Encyclopaedia of Plants.
Very interesting reading, giving some details of plant uses and quite a lot of folk-lore.
[14]Holtom. J. and Hylton. W. Complete Guide to Herbs.
A good herbal.
[17]Clapham, Tootin and Warburg. Flora of the British Isles.
A very comprehensive flora, the standard reference book but it has no pictures.
[20]Riotte. L. Companion Planting for Successful Gardening.
Fairly good.
[21]Lust. J. The Herb Book.
Lots of information tightly crammed into a fairly small book.
[55]Harris. B. C. Eat the Weeds.
Interesting reading.
[57]Schery. R. W. Plants for Man.
Fairly readable but not very comprehensive. Deals with plants from around the world.
[61]Usher. G. A Dictionary of Plants Used by Man.
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.
[62]Elias. T. and Dykeman. P. A Field Guide to N. American Edible Wild Plants.
Very readable.
[100]Polunin. O. Flowers of Europe - A Field Guide.
An excellent and well illustrated pocket guide for those with very large pockets. Also gives some details on plant uses.
[106]Coon. N. The Dictionary of Useful Plants.
Interesting reading but short on detail.
[115]Johnson. C. P. The Useful Plants of Great Britain.
Written about a hundred years ago, but still a very good guide to the useful plants of Britain.
[142]Brouk. B. Plants Consumed by Man.
Readable but not very comprehensive.
[147]? A Barefoot Doctors Manual.
A very readable herbal from China, combining some modern methods with traditional chinese methods.
[165]Mills. S. Y. The Dictionary of Modern Herbalism.
An excellent small herbal.
[169]Buchanan. R. A Weavers Garden.
Covers all aspects of growing your own clothes, from fibre plants to dyes.
[177]Kunkel. G. Plants for Human Consumption.
An excellent book for the dedicated. A comprehensive listing of latin names with a brief list of edible parts.
[179]Reid. B. E. Famine Foods of the Chiu-Huang Pen-ts'ao.
A translation of an ancient Chinese book on edible wild foods. Fascinating.
[183]Facciola. S. Cornucopia - A Source Book of Edible Plants.
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.
[187]Phillips. R. & Rix. M. Perennials Volumes 1 and 2.
Photographs of over 3,000 species and cultivars of ornamental plants together with brief cultivation notes, details of habitat etc.
[192]Emboden. W. Narcotic Plants
A lot of details about the history, chemistry and use of narcotic plants, including hallucinogens, stimulants, inebriants and hypnotics.
[200]Huxley. A. The New RHS Dictionary of Gardening. 1992.
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
[201]Allardice.P. A - Z of Companion Planting.
A well produced and very readable book.
[213]Weiner. M. A. Earth Medicine, Earth Food.
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.
[218]Duke. J. A. and Ayensu. E. S. Medicinal Plants of China
Details of over 1,200 medicinal plants of China and brief details of their uses. Often includes an analysis, or at least a list of constituents. Heavy going if you are not into the subject.
[238]Bown. D. Encyclopaedia of Herbs and their Uses.
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.
[240]Chopra. R. N., Nayar. S. L. and Chopra. I. C. Glossary of Indian Medicinal Plants (Including the Supplement).
Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.
[244]Phillips. R. & Foy. N. Herbs
Deals with all types of herbs including medicinal, culinary, scented and dye plants. Excellent photographs with quite good information on each plant.
[245]Genders. R. Scented Flora of the World.
An excellent, comprehensive book on scented plants giving a few other plant uses and brief cultivation details. There are no illustrations.
[254]Chevallier. A. The Encyclopedia of Medicinal Plants
An excellent guide to over 500 of the more well known medicinal herbs from around the world.
[272]Manandhar. N. P. Plants and People of Nepal
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.
[279] Medicinal Plants in the Republic of Korea
An excellent book with terse details about the medicinal uses of the plants with references to scientific trials. All plants are described, illustrated and brief details of habitats given.
[301]Karalliedde. L. and Gawarammana. I. Traditional Herbal Medicines
A guide to the safer use of herbal medicines.

Readers comment                                         
Elizabeth H.
david Nicholls Mon Mar 5 10:14:17 2001
I tried using the root to quit smoking after also reading in "A modern Herbal" that it is used when Peruvian Bark fails, Peruvian bark containing quinine, the active ingredient in the best quit smoking aid (for me personally), Nicobrevin. Maybe many things for fever have potential as quit smoking aids.

I'm sure it did eliminate the desire for a smoke, didn't have one for 2 hours, one every 15 mins being my usual, had about 4mm-6mm sqaure of root , then also tried about the same of rhizome, taste the same(Potters say the rhiozme is often called the root so I tried both) same effect (obviously this is only vaugely scientific).

After finding I had to keep taking it every few hours I decided I was not prepared to take such large amounts for fear of hallucinations or other risks, maybe worth researhing, I hope & think no one could patent the idea with it's folk history, so pharmaceutical corporations probably wouldn't bother with it.

Note: I can't recommend it to anyone as safe.

Elizabeth H.
T. Matin Sat Feb 16 2008
The rumor that this plant is toxic was propogated by a lab 'study' done (I think by or for the FDA) where huge amounts of Calamus was given to rats for extended periods of time. The rats grew tumors. It is perfectly safe to: A. Take a relatively large dose over a short period or B. Take a relatively small dose over a longer period of time. In general, the rule is to start with a small amount in order to aclimate yourself (and the plant) to each other. Hallucinations, if they happen, will probably not kill you, they may in fact teach you something if you just relax and take them for what they are. But I do not consider this plant as primarily a 'hallucinogen', it is of great medicinal value. But you have to trust it if you want your organism to benefit.
Elizabeth H.
dr yogesh kumar Tue Mar 18 2008
i want to know more in acorus its scientific reaserch on children ,good collectionof knowledge
Elizabeth H.
Dian Rakhmawati Harsono Sat Jun 20 2009
I've never been known abaut Acorus calamus, I'm not sure, its plant are in my country, Indonesia. Can You tell me, what is Indonesian called on Acorus calamus. Thank you
Elizabeth H.
frann leach Thu Oct 15 2009

US Food and Drug Administration Code of Federal Regulations Title 21 Regulations prohibiting the use of this plant or its extracts in the US

QR Code

What's this?

This is a QR code (short for Quick Response) which gives fast-track access to our website pages. QR Codes are barcodes that can be read by mobile phone (smartphone) cameras. This QR Code is unique to this page. All plant pages have their own unique code. For more information about QR Codes click here.

1. Copy and print the QR code to a plant label, poster, book, website, magazines, newspaper etc and even t-shirts.
2. Smartphone users scan the QR Code which automatically takes them to the webpage the QR Code came from.
3. Smartphone users quickly have information on a plant directly for the pfaf.org website on their phone.
Rate This Plant                                         
Please rate this plants for how successful you have found it to be. You will need to be logged in to do this. Our intention is not to create a list of 'popular' plants but rather to highlight plants that may be rare and unusual and that have been found to be useful by website users. This hopefully will encourage more people to use plants that they possibly would not have considered before.
Add a comment/link                                         

If you have important information about this plant that may help other users please add a comment or link below. Only comments or links that are felt to be directly relevant to a plant will be included. If you think a comment/link or information contained on this page is inaccurate or misleading we would welcome your feedback at admin@pfaf.org. If you have questions about a plant please use the Forum on this website as we do not have the resources to answer questions ourselves.

* Please note: the comments by website users are not necessarily those held by PFAF and may give misleading or inaccurate information.

Subject : Acorus calamus  

Links To add a link to another website with useful info add the details here
Name of Site
URL of Site