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Calamus (Acorus calamus L.)

Also known as sweet flag, sweetflag.

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Range - Expand

Introduced or Not Present

This tentative map is based on our own research. It may have limited data on Canada and/or Mexico, and there is some subjectivity in our assignment of plants as introduced vs. expanded. Read more in this blog post.


Used in traditional medicine, but not considered safe for regular use. Banned for use in food in the U.S. since 1968. (source)

The essential oil is used as a fragrance in perfumes.

It is sometimes cultivated as a plant for ponds.

Related to the native Acorus americanus, and some sources do not distinguish the two species. As such, it can be difficult to tell whether material written about either of these species refers to only one, or both species.

Acorus calamus (Sweet Flag) | Illinois Wildflowers (About This Site)

Acorus calamus (Calamus) | USDA PLANTS Database (About This Site)

Acorus calamus | Go Botany (About This Site)

Acorus calamus (Sweet Flag) | Missouri Botanical Garden Plant Finder (About This Site)

Acorus calamus | Biota of North America Project (BONAP) (About This Site)

Acorus calamus | NatureServe Explorer (About This Site)

Acorus calamus | Flora of North America (About This Site)

Sweetflag | Maryland Biodiversity Project (About This Site)