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Cressler, Alan

Pycnanthemum incanum

Pycnanthemum incanum (L.) Michx.

Hoary Mountain Mint, Silverleaf Mountain Mint

Lamiaceae (Mint Family)

Synonym(s):

USDA Symbol: pyin

USDA Native Status: L48 (N), CAN (N)

This stiff, erect, clump-forming mint has whitened leaves subtending the flower clusters. The minty-smelling plants are 2-6 ft. tall and have terminal flower clusters composed of numerous, small, two-lipped corollas varying from whitish to lavender, with purple spots. Flowers are in dense rounded clusters in leaf axils or atop a hairy square stem and branches; white bracts beneath flowers.

The genus name derives from the Greek for "dense" and "flower" and aptly describes the crowded flower clusters. The many species are closely related and difficult to distinguish from one another. These plants, particularly the flower clusters, have a very strong odor when crushed.

From the Image Gallery

22 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Herb
Fruit Type: Nut
Size Notes: Up to about 6 feet tall.
Fruit: Nutlets.

Bloom Information

Bloom Color: White , Purple
Bloom Time: Jun , Jul

Distribution

USA: AL , CT , DC , DE , FL , GA , IL , IN , KY , MA , MD , MI , MS , NC , NH , NJ , NY , OH , PA , RI , SC , TN , VA , VT , WV
Canada: ON
Native Distribution: S.w. NH & NY to s. OH & s. IL, s. to GA & MS
Native Habitat: Thickets; pastures

Growing Conditions

Water Use: Low , Medium
Light Requirement: Sun , Part Shade
Soil Moisture: Dry , Moist
Soil pH: Acidic (pH<6.8)
Soil Description: Mesic to dry, rich soils.
Conditions Comments: Can become invasive but is easily controlled by division every 3-5 years. Foliage in direct sun can become scorched.

Benefit

Use Ornamental: Valued primarily for its silvery foliage, secondarily for its flowers.
Conspicuous Flowers: yes
Interesting Foliage: yes
Fragrant Foliage: yes
Attracts: Butterflies
Nectar Source: yes
Deer Resistant: No

Value to Beneficial Insects

Special Value to Native Bees
Special Value to Bumble Bees
Special Value to Honey Bees
Supports Conservation Biological Control

This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.

Propagation

Description: Best propagated by cuttings or divisions. Tip cuttings are easy and reliable, taken in June. To make divisions, lift the clump in late fall or early spring and use pruning shears to divide the shallow root system. Seeds are so tiny it is best to plant
Seed Collection: Collect seed after the first few frosts. To check for ripe seed, bend over the stem and shake it; if black seeds fall out, collect right away. Store in sealed, refrigerated containers.
Seed Treatment: No pretreatment necessary.
Commercially Avail: yes

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:

Mt. Cuba Center - Hockessin, DE

Bibliography

Bibref 1620 - Gardening with Native Plants of the South (Reprint Edition) (2009) Wasowski, S. with A. Wasowski

Search More Titles in Bibliography

Web Reference

Webref 34 - Go Botany (2019) Native Plant Trust
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter

Additional resources

USDA: Find Pycnanthemum incanum in USDA Plants
FNA: Find Pycnanthemum incanum in the Flora of North America (if available)
Google: Search Google for Pycnanthemum incanum

Metadata

Record Modified: 2023-02-23
Research By: TWC Staff

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