Acorus calamus L.

Comments: An individual with the U.S. herbal medicinal industry states that trade in the plant is modest, on the order of 2000-3000 pounds per year, and that it is the root that is used (McGuffin pers. comm.).

In northeastern South Dakota, the Dakota tribe collects and utilizes an unknown quantity of this plant (David Ode pers. comm.). It is reportedly collected in Canada and the northeastern U.S. for sale on the herb market (Robyn Klein pers. comm.).

Acorus calamus is listed by the United Plant Savers At Risk Forum on their "To Watch" list. This list consists of "herbs which are broadly used in commerce and which, due to over-harvest, loss of habitat, or by the nature of their innate rareness or sensitivity are either at risk or have significantly declined in numbers within their current range." (United Plant Savers 2000)

With the general disappearance and degradation of wetlands, the habitat of this species continues to shrink. Because it is associated with relatively undisturbed habitats when compared with Acorus calamus, A. americanus is probably more threatened in some parts of its range as more undisturbed wetlands become disturbed. Replacement of A. americanus by A. calamus is possible as more wetland habitats become disturbed where the two species overlap. Channelization of springruns has been implicated as a threat to occurrences of this species in Georgia (Tom Patrick pers. comm.). Urban sprawl is causing widespread degradation of potential habitat for this species in southern Lower Michigan (Mike Penskar pers. comm.). Lack of monitoring resources available to properly document the population trends for this species are cited as a threat in Mississippi (Mississippi Natural Heritage Program).

Sweet flag can be propagated vegetatively by plant or rhizome division, and by seed. Vegetative propagation is best completed in the fall or spring using firm, healthy rhizomes cut into 2- to 4-inch sections. Plant sections in rich soil 4 - 6 inches deep and 1 foot apart. Separating individual sprigs from clumped plants is an alternative to using rhizomes. These should also be transplanted at 1-foot spacings.

Seed should be planted during the fall or winter in a greenhouse. Fill a 2-inch deep tray with an organic

soil mix, scatter seed sparsely on the surface and press firmly into the soil. Do not bury further than 1/8 inch deep. Keep soil moist to saturated. Seed does not require stratification and germinates in less than 2 weeks. When plants reach 3 to 4 inches transplant into individual 4-inch pots. Pots can be placed in shallow water or irrigated frequently to maintain very moist to saturated conditions. Transplant outdoors 1 foot apart in the spring. With adequate moisture seed can also be planted outdoors spring through early summer, or in a cold frame late summer through fall.

Sweet flag is a perennial, rhizomatous, iris-like herb. The erect, sharp-pointed, sword-shaped leaves fan-out from a pinkish base and grow to 5 feet in length. The midvein is usually off-center. Cut or bruised leaves produce a sweet, tangerine-like scent. The flower stem, or scape, arises from the base of the outer leaves. Although resembling a leaf, the scape is triangular in cross section. A long, erect bract, or spathe, extends beyond the scape. A single, cylindrical 2 to 4-inch spike, or spadex, angles upward at this union. The slightly curved spadix is crowded with small yellowish-green to brown flowers that appear from May to July. Sweet flag has thick, creeping rhizomes with brownish exteriors and white, fleshy interiors.

Muskrats are fond of the rootstocks and readily consume them. Otherwise, little information is available about floral-faunal relationships.