Marsh Hedge Nettle is an erect native perennial forb growing to 40 inches high on 4-angled stems with little branching. Stems are light green, sometimes purplish, with fine stiff, somewhat downward pointing hair on all sides of the stem, not just on the angles.
The leaves are opposite, thick, oblong to lance-shaped with rounded or heart-shaped bases, hairy surfaces, a fine reticulated network of veins and saw-toothed edges. They are either stalkless or with very short stalks which are most likely found on the lower stem leaves.
The inflorescence is a terminal spike with interrupted whorl-like clusters of 6 to 10 flowers around the stem - usually 6 but always an even number. The clusters appear just above the leaf axils. There are several leafy bracts under each whorl. In the mint family this arrangement is called a 'verticillaster' where the flowers look like a whorl arrangement but are actually in cymes that rise from the axils of opposite bracts.
The flowers are stalkless, 3/8 to 2/3 inch long with a short tubular green calyx that is bristly-hairy and has 5 awl shaped teeth that are more than half as long as the corolla tube. The corolla, longer than the calyx, with 2 lips that are white to pink to pale purple and spotted with a deeper purple. The upper lip is not divided and has a hairy convex outer surface. The lower lip has 3 spreading lobes, the center lobe being broader that the lateral lobes. There are 4 stamens in pairs of unequal length, with dark purple anthers, that rest against the upper lip. The style also is tucked under the upper lip.
Seed: Each fertile flower produces a seed capsule containing 4 small ovoid nutlets which disperse by wind shaking the stem or by compression of the drying calyx they are shot out.
Habitat: Marsh Hedge Nettle is found in wet meadows, riparian areas, moist prairies and grasslands. Soils should be loamy to sandy, moisture wet-mesic. The plant tolerates and will flower in light shade but full sun is best. It grows form a rhizomatous root system and can re-generate from the root system and from seeds.
Names: The genus, Stachys, is taken from the Greek word Stachus, meaning 'a spike', and refers to to the spike-like form of the inflorescence of this genus. The species, palustris, means 'of marshes' and is frequently applied to plants found in moist areas. As to the common names, see notes at page bottom. The author name for the plant classification - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Varieties and name changes: There are a large number of varieties of S. palustris that have been classified over the years resulting from variation in leaf size and the amount of stem and leaf hair. In Minnesota only two have been recognized: Var. homotricha and var. pilosa. The former is found in sandy environments. The University of Minnesota Herbarium currently reports that those two varieties are now going to be assigned to Stachys pilosa as var. pilosa, the Hairy Hedgenettle. As this is new botanical work, very few other references have further information on this.
Comparisons: The second species of Hedge-nettle in Minnesota is S. tenuifolia, the Smooth Hedge-nettle, where the stem only has hair on the stem angles, not all over and the leaves are thin, not thick. The third species of Stachys found in Minnesota is S. pilosa, Hairy Hedge-nettle, the species into which the former Minnesota varieties of S. palustris are being re-classified. The other plants of the mint family that will resemble this plant are American Germander, Teucrium canadense, where the upper lip is much smaller and the stamens more prominent. Also look at Wild Mint, Mentha arvensis.
Above: The inflorescence is a series of verticillasters where the flowers look like a whorl arrangement but are actually in cymes that rise from the axils of opposite bracts. Drawing by Norman Criddle.
Below: 1st photo - The green calyx is bristly-hairy with 5 awl shape teeth. The undivided upper lip of the corolla has hair on the outside, the center lower lobe is the largest. Flowers occur in cymes of 6 to 10 flowers. 2nd photo - The design of the verticillaster can be seen here where the cluster of 6 is obviously grouped in a cyme of 3 opposite each other.
Below: 1st photo - The corolla, longer than the calyx, with 2 lips that are white to pink to pale purple and spotted with a deeper purple. The upper lip is not divided and has a hairy convex outer surface. The short tubular green calyx that is bristly-hairy has 5 awl shaped teeth that are more than half as long as the corolla tube. 2nd photo - The underside of a leaf showing the fine hair on the surface especially on the ribs, main vein and margins. Not the fine reticulated vein network.
Below: 1st photo - The 4 stamens in pairs of unequal length, with dark purple anthers, rest against the upper lip. 2nd photo - The leaf and plant (3rd photo) show an example where the leaves are more oblong with a rounded base, rather than lance-shaped.
Below: 1st photo - Stems may have stiff hair; the opposite leaves have hairy surfaces. 2nd photo - seed capsules are forming on the lower stem while the upper whorls still have open flowers. 3rd photo - Seed capsules develop within the calyx tube (note the 5 long awl shape teeth) which hold the capsule until seeds are mature.
Notes: Marsh Hedge-nettle is not indigenous to the Garden. Eloise Butler brought in plants from Zumbra Heights (Lake Zumbra near Lake Minnetonka) on August 12, 1910 and 7 more plants from Mendota on Oct. 16, 1917. More were added in '18 and '19. She also brought in a plant that is not found in Minnesota, the Rough Hedge-nettle, S. aspera, in 1912 from Kelsey's Nursery in North Carolina where the plant is native. By the time of Martha Crone's 1951 Garden Census, S. palustris was gone, but S. aspera was still present. On the 1986 census, S. palustris was present once again but on the 2009 census neither was present. Marsh Hedge-nettle is found in the NE Quadrant of North America with Minnesota and Manitoba at the western edge of the range and the south end of the range extends from Illinois eastward to New Jersey, excepting Indiana. It is considered as introduced in the Canadian Provinces.
In Minnesota S. palustris and its varieties are found throughout the state with very few counties excepted. The University of MN Herbarium lists 3 species of Stachys as found in Minnesota, this one plus S. pilosa and S. tenuifolia and as mentioned above, USDA considers one a synonym for the other but the U of M Herbarium and the DNR Do not recognize that combination. The MN DNR still line lists the two sub-species of S. palustris, but with reported locations only at the species level.
Names and folk use: A number of plants of the genus Stachys have 'Woundwort' as part of the common name. Mrs. Grieve (Ref. #7) believes this goes back to the rustic surgery of medieval times when the leaves of Stachys, with their fine hair, were used in place of lint to bind wounds and staunch the flow of blood. The term 'hedge-nettle' is probably from England where the plant is found frequently in the hedgerows and it resembles a nettle. Densmore (Ref.#7) reports the Minnesota Chippewa used the fresh or dry leaves to treat colic by putting them in hot water to create an infusion to drink. Tilford (Ref. #39) reports that the plant is used in herb medicine in the western states as a general anti-inflammatory medicine, although the leaves have a bitter taste.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"