Butterflies favor this plant because it is a good source of nectar. (Pycnanthemum muticum in American Beauties Native Plants fact sheet, accessed 16 November 2007). The leaves have a strong mint fragrance that can even be smelled in museum specimens decades old.
There are 11 existing populations but most of them have fewer than 50 plants. There are about 10 historical records but many of these are from developed areas from New York City to Long Island and around Rochester. More populations could be found as its habitat preferences are better understood.
More survey work is needed to understand the short-term trends since most populations have only been surveyed once.
Most of the original historical records are from areas that have been developed but new populations have been discovered to keep the total number of populations about the same over time.
For plants located close to the road any construction from the road may negatively impact the population if the road crew is not made aware of its presence. More studies are needed to determine if run-off from the road is a threat. Other populations are located close to human activity which may inadvertently harm plants.
Avoid mowing plants along roadsides during the growing season. Establish sufficient buffers around populations to preserve the undisturbed aspect and hydrology of their habitat.
Research is needed to determine what is limiting the spread of this species since there seems to be plenty of habitat into which it could grow.
In New York most of our extant sites for Pycnanthemum muticum consist of wet, sandy, coastal habitats. These include wet swales between dunes, the shores of coastal plain ponds, red-maple-sweetgum swamps, and wet roadside shrub thickets. There is also a single extant site inland along a railroad embankment (New York Natural Heritage Program 2007). Moist woods, thickets, meadows, and swales (Rhoads and Block 2000). Moist woods and meadows (Gleason and Cronquist 1991). Dry (or somewhat wet) woods, thickets, and clearings (Fernald 1970).
Most of the extant New York populations are located on the South Fork of eastern Long Island. There is also one current record Staten Island and one from Orange County. There are historical records scattered elsewhere in Western New York and up the Hudson Valley to Washington County.
Pycnanthemum muticum is found in all the states east of the Mississippi, excepting Maine (from which it is believed to be extirpated), Indiana, and Wisconsin. It is also found in Texas, Louisiana, Arkansas, and Missouri.
Pycnanthemum muticum is a rhizomatous herb with a branching, pubescent, square stem up to 1 m tall. Like other Mountain-mints it is strongly aromatic, such that a strong spearmint odor from the leaves may be the explorer's first clue to its presence. A main field characteristic of Pycnanthemum muticum is its firm, thick, dark green leaves. These are broadly oval, with a pointed tip, and round or heart-shaped leaf bases. They range from 1 to 4 cm wide and are usually no more than twice as long as wide. The middle stem leaves are typically glabrous to waxy above, while the upper inflorescence leaves are velvety. The flowers are crowded in rounded heads at the top of the stems. They are 2-lipped, the petals are white or pale violet with many purple spots. The teeth of the calyx are all triangular to acuminate (long-pointed).
Blunt Mountain-mint is best identified when flowering or fruiting.
In New York misidentifications of Pycnanthemum muticum usually turn out to be P.virginianum, P. verticillatum, or rarely P. incanum. Pycnanthemum virginianum and P. verticillatum typically have leaves at least 3 times as long as wide, and only rarely over 1.5 cm wide. Pycnanthemum muticum leaves are usually not more than 2 times as long as wide and range from 1 to 4 cm wide. Pycnanthemum incanum, as well as P. clinopodioides, have a bilabiate calyx, with the upper and lower calyx teeth of unequal lengths.
This species flowers in mid-July to early September, with the fruits persisting through the first frost.
The time of year you would expect to find Blunt Mountain Mint flowering and fruiting in New York.
Blunt Mountain Mint
Pycnanthemum muticum (Michx.) Pers.
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Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York
Weldy, Troy W. and David Werier. 2005. New York Flora Atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research. University of South Florida]. New York Flora Association, Albany, NY. Available on the web at (http://newyork.plantatlas.usf.edu/).
Information for this guide was last updated on: December 22, 2008
Please cite this page as:
New York Natural Heritage Program. 2020. Online Conservation Guide for Pycnanthemum muticum. Available from: https://guides.nynhp.org/blunt-mountain-mint/. Accessed September 26, 2020.