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NPIN: Native Plant Database

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Acorus calamus (Calamus)
Wasowski, Sally and Andy

Acorus calamus

Acorus calamus L.

Calamus, Single-vein sweetflag, Sweet flag

Araceae (Arum Family)


USDA Symbol: ACCA4

USDA Native Status: L48 (I), CAN (I)

A grasslike, aromatic perennial with long, narrow, erect leaves rising to a height of 5 ft. and a distinctive inflorescence. This plant emerges from the water with a 2-edged stalk, with an outward-jutting club-like spadix bearing tiny, greenish-yellow flowers. Individual flowers are small and inconspicuous, crowded on a fleshy stalk (spadix) which resembles the leaves. A narrow, foot-long spathe (specialized leaf), projects beyond the spadix.

This plant, which grows partly in and partly out of water, reproduces by underground rootstalks that have a sweet odor and flavor, once used for making candy. All parts of the plant are fragrant when bruised.


Plant Characteristics

Duration: Perennial
Habit: Herb
Leaf: Green
Size Class: 3-6 ft.

Bloom Information

Bloom Color: Yellow , Green
Bloom Time: Jun , Jul , Aug


USA: AL , AR , CA , CO , CT , DC , DE , GA , IA , IL , IN , KS , KY , LA , MA , MD , ME , MI , MN , MO , MS , NC , NE , NH , NJ , NY , OH , OK , OR , PA , RI , SC , SD , TN , TX , VA , VT , WA , WI , WV
Canada: SK
Native Distribution: P.E.I. to scattered locales in MT, ID, OR & n. CA, s. to SC & TX
Native Habitat: Pond borders; wet places

Growing Conditions

Water Use: High
Light Requirement: Sun , Part Shade
Soil Moisture: Moist , Wet
Soil pH: Acidic (pH<6.8)
CaCO3 Tolerance: Medium
Soil Description: Wet soil.
Conditions Comments: An aromatic plant suitable for wet areas. Botanists argue whether this is a native North American plant or an early introduction, naturalized, from Eurasia.


Fragrant Flowers: yes
Fragrant Foliage: yes


Description: Propagate by root cuttings. Plant the forward end of the large root with the fiber roots spread out straight and the rhizome lying horizonally just below the soil surface. Seeds germinate fairly well in wet soil, but the plant makes few seeds, being nea
Seed Collection: Not Available
Seed Treatment: Not Available
Commercially Avail: yes

Mr. Smarty Plants says

Native plants to stop pond bank erosion
June 04, 2008
I recently purchased a home with a small pond in which a nearby stream daylights. The former owner placed large field stone around the pond and the small stream; however, the area around the pond and...
view the full question and answer

National Wetland Indicator Status

This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

From the National Suppliers Directory

According to the inventory provided by Associate Suppliers, this plant is available at the following locations:

Edge of the Woods Native Plant Nursery - Orefield, PA
Sunshine Farm & Gardens - Renick, WV

Additional resources

USDA: Find Acorus calamus in USDA Plants
FNA: Find Acorus calamus in the Flora of North America (if available)
Google: Search Google for Acorus calamus


Record Modified: 2007-12-23
Research By: TWC Staff

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