• Photo of Pycnanthemum incanum (Pycnanthemum incanums)

Plant Profile: Pycnanthemum incanum

Taxonomy: Pycnanthemum incanum

Names

Hoary Mountainmint, Hoary Mountain Mint, Hoary Mountain-mint, Mountain Mint, Silverleaf Mountain-mint

  • Photo of Pycnanthemum incanum (Pycnanthemum incanums)

Phonetic Spelling:pik-NAN-thee-mum in-KAN-num

Genus:Pycnanthemum

Species:incanum

Family:Lamiaceae

Hoary mountain-mint, named for the silvery-white appearance of its upper leaves and the bracts beneath its flower clusters, belongs to the Lamiaceae family. This upright, multi-branched perennial typically reaches heights of 2 to 3 feet, characterized by its square stems, a common trait among mint family members. It serves as an effective erosion control plant, is drought-resistant, and thrives in arid soil conditions. Its ability to root from stems and self-seed allows it to naturalize in various landscapes, so it's important to be mindful of its potential to become weedy.

As an herbaceous perennial, Hoary Mountain-mint can grow up to 5 feet tall, with stems densely covered in short white hairs. The leaves are arranged oppositely, featuring a serrated edge and a white upper surface. The plant produces white or lilac flowers adorned with purple spots, which begin to bloom in mid-summer and persist into early fall.

Fire Risk: This species has a medium flammability rating.

Seasons of Interest:
- Bloom: Summer, Fall
- Fruit/Nut/Seed: Fall

For additional details on Pycnanthemum, please refer to further resources.

Pycnanthemum incanum Feature Summary

Pycnanthemum incanum Image Gallery

Tags

#showy flowers
#fragrant flowers
#drought tolerant
#fall flowers
#perennial
#white flowers
#wildlife plant
#purple flowers
#showy
#weedy
#fragrant leaves
#native perennial
#herb garden
#fire
#medium flammability
#NC native
#insect pest tolerant
#summer flowers
#deer resistant
#herbaceous perennial
#native garden
#naturalizes
#pollinator plant
#native wildflower
#wildflower garden
#larval host plant
#food source fall
#NC Native Pollinator Plant
#food source nectar
#food source pollen
#butterfly friendly
#nectar plant mid-summer
#nectar plant late summer
#pollinator garden
#audubon
#wavy-lined emerald butterfly
#stormwater demo garden orange co

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Pycnanthemum incanum Feature Summary

Attributes
Eastern U.S.A. to Indiana
This plant supports Wavy-lined Emerald (Synchlora aerata) larvae. This plant provides nectar for pollinators. Flowers are attractive to butterflies, especially smaller species like hairstreaks, and many other insects.
Hoary mountain-mint is highly deer resistant.
Leaves and flowers used for tea
Perennial
medium flammability
Fruit
Displays from September to October.
< 1 inch
Flowers
Cluster of small, lobed, two-lipped, whitish to lavender flowers with small purple spots; hoary bracts below the flower. Blooms June to August.
Purple/Lavender
White
< 1 inch
Leaves
1.5 to 4 in. egg- to lance-shaped, toothed, opposite, stalked leaves with white down (hoary) below.
Green
Gray/Silver
White
Ovate
Lanceolate
1-3 inches
Edible
Fragrant
Good Dried
1-3 inches
Stem
Green
Gray/Silver
White
Hairy (pubescent)
Whole Plant Traits
Perennial
Edible
Herbaceous Perennial
Native Plant
Wildflower
Herb
Cultural Conditions
Full sun (6 or more hours of direct sunlight a day)
Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Good Drainage
Moist
Occasionally Dry
Mountains
Piedmont
4a
4b
5b
5a
6a
6b
7a
7b
8b
8a
Landscape
Edible Garden
Butterfly Garden
Pollinator Garden
Native Garden
Drought
Deer
Dry Soil
Erosion
Woodland
Naturalized Area
Butterflies
Pollinators
Bees

Pycnanthemum incanum Attributes

Pycnanthemum incanum: Country Or Region Of Origin

Eastern U.S.A. to Indiana

Pycnanthemum incanum: Wildlife Value

This plant supports Wavy-lined Emerald (Synchlora aerata) larvae. This plant provides nectar for pollinators. Flowers are attractive to butterflies, especially smaller species like hairstreaks, and many other insects.

Pycnanthemum incanum: Particularly Resistant To (Insects/Diseases/Other Problems)

Hoary mountain-mint is highly deer resistant.

Pycnanthemum incanum: Edibility

Leaves and flowers used for tea

Pycnanthemum incanum: Life Cycle

Annual
Biennial
Bulb
Perennial
Woody

Pycnanthemum incanum: Recommended Propagation Strategy

Division
Grafting
Layering
Leaf Cutting
Root Cutting
Seed
Stem Cutting

Pycnanthemum incanum: Fire Risk Rating

extreme flammability
high flammability
low flammability
medium flammability

Pycnanthemum incanum Fruit

Pycnanthemum incanum: Fruit Description

Displays from September to October.

Pycnanthemum incanum: Fruit Type

Achene
Aggregate
Berry
Capsule
Caryopsis
Drupe
Follicle
Legume
Nut
Pome
Samara
Schizocarp
Siliqua

Pycnanthemum incanum: Fruit Color

grass
Black

Pycnanthemum incanum: Display/Harvest Time

Fall
Spring
Summer
Winter

Pycnanthemum incanum: Fruit Length

< 1 inch
1-3 inches
> 3 inches

Pycnanthemum incanum: Fruit Width

< 1 inch
1-3 inches
> 3 inches

Pycnanthemum incanum Flowers

Pycnanthemum incanum: Flower Description

Cluster of small, lobed, two-lipped, whitish to lavender flowers with small purple spots; hoary bracts below the flower. Blooms June to August.

Pycnanthemum incanum: Flower Color

filter_vintage
Purple/Lavender
filter_vintage
White

Pycnanthemum incanum: Flower Inflorescence

Catkin
Corymb
Cyme
Head
Insignificant
Panicle
Raceme
Solitary
Spadix
Spike
Umbel

Pycnanthemum incanum: Flower Value To Gardener

Edible
Fragrant
Good Cut
Good Dried
Long Bloom Season
Long-lasting
Showy

Pycnanthemum incanum: Flower Bloom Time

Winter
Spring
Summer
Fall

Pycnanthemum incanum: Flower Shape

Bell
Cross
Crown
Cup
Dome
Funnel
Irregular
Lipped
Radial
Saucer
Star
Trumpet
Tubular
Urn
Wheel

Pycnanthemum incanum: Flower Size

1-3 inches
3-6 inches
< 1 inch
> 6 inches

Pycnanthemum incanum Leaves

Pycnanthemum incanum: Leaf Description

1.5 to 4 in. egg- to lance-shaped, toothed, opposite, stalked leaves with white down (hoary) below.

Pycnanthemum incanum: Woody Plant Leaf Characteristics

Broadleaf Evergreen
Deciduous
Needled Evergreen
Semi-evergreen

Pycnanthemum incanum: Leaf Color

spa
Gray/Silver
spa
Green
spa
White

Pycnanthemum incanum: Leaf Type

Compound (Pinnately , Bipinnately, Palmately)
Fronds
Needles
Sheath
Simple

Pycnanthemum incanum: Leaf Arrangement

Alternate
Opposite
Other/more complex
Rosulate
Whorled

Pycnanthemum incanum: Leaf Shape

Acicular
Auriculate
Cordate
Cuneate
Deltoid
Elliptical
Filiform
Lanceolate
Linear
Oblanceolate
Oblong
Obovate
Obtuse
Orbicular
Ovate
Palmasect
Palmatifid
Peltate
Pinnatifid
Pinnatisect
Reniform
Rhomboidal
Spatulate
Subcordate
Subulate

Pycnanthemum incanum: Leaf Margin

Crenate
Crenulate
Dentate
Denticulate
Doubly Crenate
Doubly Dentate
Doubly Serrate
Entire
Lobed
Serrate
Sinuate
Undulate

Pycnanthemum incanum: Hairs Present

No
Yes

Pycnanthemum incanum: Leaf Length

< 1 inch
1-3 inches
3-6 inches
> 6 inches

Pycnanthemum incanum: Leaf Feel

Fleshy
Glossy
Leathery
Papery
Prickly
Rough
Rubbery
Slippery
Smooth
Soft
Velvety
Waxy

Pycnanthemum incanum: Leaf Value To Gardener

Edible
Fragrant
Good Cut
Good Dried
Long-lasting
Showy

Pycnanthemum incanum: Leaf Width

< 1 inch
1-3 inches
3-6 inches
> 6 inches

Pycnanthemum incanum Stem

Pycnanthemum incanum: Stem Description

Hoary stems

Pycnanthemum incanum: Stem Color

grass
Gray/Silver
grass
Green
grass
White

Pycnanthemum incanum: Stem Is Aromatic

No
Yes

Pycnanthemum incanum: Stem Cross Section

Angular
Oval
Round
Square

Pycnanthemum incanum: Stem Surface

Corky Ridges
Covered with a powdery bloom (glaucous)
Dull
Hairy (pubescent)
Polished
Smooth (glabrous)

Pycnanthemum incanum Whole Plant Traits

Pycnanthemum incanum: Plant Type

Annual
Bulb
Carnivorous
Edible
Epiphyte
Fern
Ground Cover
Herb
Herbaceous Perennial
Houseplant
Mushroom
Native Plant
Ornamental Grasses and Sedges
Perennial
Poisonous
Rose
Shrub
Succulent
Tree
Turfgrass
Vegetable
Vine
Water Plant
Weed
Wildflower

Pycnanthemum incanum: Woody Plant Leaf Characteristics

Broadleaf Evergreen
Deciduous
Needled Evergreen
Semi-evergreen

Pycnanthemum incanum: Habit/Form

Arching
Ascending
Broad
Cascading
Climbing
Clumping
Columnar
Conical
Creeping
Dense
Erect
Horizontal
Irregular
Mounding
Multi-stemmed
Multi-trunked
Open
Oval
Prostrate
Pyramidal
Rounded
Spreading
Vase
Weeping

Pycnanthemum incanum: Maintenance

Low
Medium
High

Pycnanthemum incanum Cultural Conditions

Pycnanthemum incanum: Light

Dappled Sunlight (Shade through upper canopy all day)
Deep shade (Less than 2 hours to no direct sunlight)
Full sun (6 or more hours of direct sunlight a day)
Partial Shade (Direct sunlight only part of the day, 2-6 hours)

Pycnanthemum incanum: Soil Drainage

Frequent Standing Water
Good Drainage
Moist
Occasional Flooding
Occasionally Dry
Occasionally Wet
Very Dry

Pycnanthemum incanum: Available Space To Plant

12 inches-3 feet
12-24 feet
24-60 feet
3 feet-6 feet
6-feet-12 feet
Less than 12 inches
more than 60 feet

Pycnanthemum incanum: NC Region

Coastal
Mountains
Piedmont

Pycnanthemum incanum: USDA Plant Hardiness Zone

thermostat
4a
thermostat
4b
thermostat
5a
thermostat
5b
thermostat
6a
thermostat
6b
thermostat
7a
thermostat
7b
thermostat
8a
thermostat
8b

Pycnanthemum incanum Landscape

Pycnanthemum incanum: Landscape Theme

Asian Garden
Butterfly Garden
Children's Garden
Cottage Garden
Cutting Garden
Drought Tolerant Garden
Edible Garden
English Garden
Fairy Garden
Garden for the Blind
Native Garden
Nighttime Garden
Pollinator Garden
Rain Garden
Rock Garden
Shade Garden
Water Garden
Winter Garden

Pycnanthemum incanum: Resistance To Challenges

Black Walnut
Compaction
Deer
Diseases
Drought
Dry Soil
Erosion
Fire
Foot Traffic
Heat
Heavy Shade
Humidity
Insect Pests
Pollution
Poor Soil
Rabbits
Salt
Slugs
Squirrels
Storm damage
Urban Conditions
Voles
Wet Soil
Wind

Pycnanthemum incanum: Landscape Location

Coastal
Container
Hanging Baskets
Houseplants
Lawn
Meadow
Naturalized Area
Near Septic
Patio
Pond
Pool/Hardscape
Recreational Play Area
Riparian
Rock Wall
Slope/Bank
Small Space
Vertical Spaces
Walkways
Woodland

Pycnanthemum incanum: Attracts

Bats
Bees
Butterflies
Frogs
Hummingbirds
Moths
Pollinators
Predatory Insects
Reptiles
Small Mammals
Songbirds
Specialized Bees

Pycnanthemum incanum: Problems

Allelopathic
Contact Dermatitis
Frequent Disease Problems
Frequent Insect Problems
Invasive Species
Malodorous
Messy
Poisonous to Humans
Problem for Cats
Problem for Children
Problem for Dogs
Problem for Horses
Short-lived
Spines/Thorns
Weak Wood
Weedy