Herbs & Plants

Pycnanthemum flexuosum

Botanical Name: Pycnanthemum flexuosum
Family : Lamiaceae (Labiatae – Mint family)
Order : Lamiales
Genus: Pycnanthemum Michx. – mountainmint
Species: Pycnanthemum flexuosum (Walter) Britton, Sterns & Poggenb. – Appalachian mountainmint

Synonyms : Koellia flexuosa.

Common Names: Appalachian Mountain Mint, Mountain Mint, Savannah Mountain Mint.

Habitat: Pycnanthemum flexuosum is native to Eastern N. America – Maine to Florida, New York, Minnesota, Kansas and Texas. It grows in upland prairies, pastures, meadows, open woodland and roadsides.

Pycnanthemum flexuosum is an upright perennial that expands slowly from shallow rhizomes. Plants grow 2-3’ tall with 3-4’ spread. The sturdy square stems are covered with fine white hairs. Aromatic leaves are arranged opposite from each other on short petioles along the stems. The blades are toothed or occasionally entire with pointed tips. They are lanceolate or narrowly elliptical and up to 2” long and about ½” wide. In autumn blades often develop red coloration along the margins.
The stems terminate in globular white to pale lavender dense head-like flower cymes. Many fragrant tubular florets are packed into the 1-1.5” wide inflorescence. Each floret is about ¼” long with a ring of united petals that is lobed toward the tip.

Blooming lasts for about 6 weeks from mid-summer to early autumn. The florets mature into ovoid nutlets that are nestled into brown button-like cymes.
It is in flower from August to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects.

Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.


Succeeds in most soils but prefers a rich loamy soil in full sun or partial shade with plenty of moisture in the growing season. Hardy to at least -15°c. The correct name for this species should be P. tenuifolium. Schrad. The bruised leaves are very aromatic. For polyculture design as well as the above-ground architecture (form – tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. The plant growth habit is a clumper with limited spread . The root pattern is rhizomatous with underground stems sending roots and shoots along their length.

Medicinal Uses:
The leaves and flowering stems are popularly used in the treatment of bowel complaints. A hot infusion of the plant is diaphoretic. The plant is also used internally in the treatment of stomach upsets, fevers, colds and sinus headaches. A poultice of the leaves is used in the treatment of headaches. A warm infusion of the plant has been used to bathe an inflamed penis. The plant is harvested as it comes into flower and can be used fresh or dried.

Other Uses:
CULTURAL & MAINTENANCE NEEDS: Pycnanthemum flexuosum thrives in sunny sites with moist well drained soil. Plants tolerate part sun, clay, seasonally wet soils, heat, humidity and drought.

Throngs of desirable pollinators flock to the blooms. The aromatic foliage is unpalatable to deer and plants are fairly resistant to other pests.

This species will slowly expand to form colonies. Since it is not aggressive, little maintenance is needed.

In manicured gardens, stems can be trimmed to the ground in late winter.

LANDSCAPE USES: The mountain mints are listed on many “Top Ten Plants for Pollinators” lists. Pycnanthemum flexuosum is a good choice for a Wildlife Garden or Meadow. Plants are also used as Butterfly Nectar Plants, Cut Flowers or as part of a Grouping or Mass Planting that will aid in Erosion Control. This species has Showy Blooms and is appropriate for Cottage Gardens, Deer Resistant Plantings, Water-wise Landscapes, Low Maintenance Plantings, Rain Gardens, Rock Gardens and Perennial Borders.

Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.


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