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American Mountain Mint

Pycnanthemum virginianum (pik-NAN-thee-mum vir-ji-nee-AY-num)

Family: Lamiaceae Native Shrub (3-15 ft)

Mountain Mint is a branching, herbaceous, flowering perennial in the Lamiaceae family that grows to 3 feet high with a bushy habit. The stems are green or red with small, 1/2 inch leaves that emit a strong mint scent when crushed. Numerous white flowers with purple dots blossom in sequence at the end of the upper stems in mid-summer, beginning with the outer circle of flowers and moving toward the center. Mountain Mint is probably misnamed, because it does not usually occur in mountainous habitats. The genus name comes from Greek pyknos meaning dense and anthos meaning flower. The species name means "of Virginia". Mountain Mint prefers full or partial sun and moist to average soil. It will tolerate most soils: loam, sand, clay, or gravel. During drought, the lower leaves can yellow and fall off. The plant will add interest to an herb garden, border, naturalized area or meadow and can also be grown in open areas near ponds and streams. The root system produces rhizomes, which spread a short distance from the mother plant forming a small colony of plants. It can be aggressive in optimum sites, but less so when the soil is kept dry. Insects are strongly attracted to the flowers, including various bees, wasps, flies, small butterflies, and beetles; however, mammals and and leaf-chewing insects seem to find the mint fragrance of the leaves and stems repugnant, and rarely bother this plant. Diseases, Insect Pests, and Other Plant Problems: This plant is less subject to foliar disease than some other mints, such as Monarda spp. However, stressed plants can succumb to rust. More information on Pycnanthemum .

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 58 attributes.

How it fits the guild

Guild layer 3 - Shrub (3-15 ft)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Often confused with Pycnanthemum tenuifolium
Fills a similar niche Baptisia alba Eupatorium perfoliatum Symphyotrichum lateriflorum

Full plant profile

Growing Conditions
Plant type
Herbaceous Perennial; Native Plant; Shrub; Wildflower
Life cycle
Perennial
USDA zones
3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Sand; Shallow Rocky
Soil drainage
Good Drainage | Moist
Available space
3 feet-6 feet
NC region
Coastal; Piedmont
Mature size
Height: 2 ft. 0 in. - 3 ft. 0 in. | Width: 1 ft. 0 in. - 1 ft. 6 in.
Growth rate
Medium
Maintenance
Low
Canopy layer
3 - Shrub (3-15 ft)
Form & Appearance
Habit / form
Dense; Erect
Foliage
Deciduous
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Opposite
Leaf shape
Lanceolate; Linear
Leaf margin
Entire
Leaf value
Fragrant
Leaf size
1-3 inches long, < 1 inch wide
Hairs present
No
Leaf detail
Leaves are up to 2½" long and narrowly lanceolate or linear. They are sessile, and have smooth margins. The largest leaves are ¼ - ½" across. When damaged, the foliage releases a strong mint scent.
Flower color
White
Flower value
Showy
Flower shape
Tubular
Flower size
< 1 inch
Flower detail
Numerous flattened heads of small white flowers (often with purple dots) occur at the ends of the upper stems. Each head is up to ¾" across and can contain up to 50 flowers. However, only a few bloom at the same time, beginning with the outer flowers moving to the center over the course of mid-Summer. Each tubular flower is about 1/8" long and 2-lipped.
Bloom time
Summer
Fruit color
Black
Fruit type
Nut
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Each small flower produces 4 tiny, finely pitted, dull black seeds. These seeds are distributed by the wind.
Stem color
Green; Red/Burgundy
Stem detail
Green or reddish stems are strongly four-angled with scattered white hairs along the ridges.
Wildlife & Ecology
Native status
Native
Origin
Eastern Canada and United States south to North Carolina.
Wildlife value
Attracts pollinators.
Attracts
Bees; Butterflies; Pollinators
Food & Medicine
Harvest time
Fall
Fruit type
Nut

Uses (ethnobotany)

Used in teas.

Landscape Use
Landscape location
Meadow; Pond; Slope/Bank
Landscape theme
Butterfly Garden; Native Garden; Pollinator Garden; Rain Garden
Design feature
Border; Mass Planting
Garden tags
#herbaceous perennial #flowering shrub #fragrant leaves #native perennial #spreading #native shrub #NC native #NC Native Pollinator Plant #pollinator garden #white flowers #full sun tolerant #native garden #rain garden #moth friendly
Problems & Resistance
Resistant to
Insect Pests; Poor Soil
Propagation
Division; Seed

Planted at Hunnicutt

Nobody’s planted this one yet.