Pycnanthemum incanum (L.) Michx.
Hoary Mountain Mint, Silverleaf Mountain Mint
Lamiaceae (Mint Family)
USDA Symbol: PYIN
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
Plant CharacteristicsDuration: Perennial
Fruit Type: Nut
Size Notes: Up to about 6 feet tall.
Bloom InformationBloom Color: White , Purple
Bloom Time: Jun , Jul
DistributionUSA: 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
Native Distribution: S.w. NH & NY to s. OH & s. IL, s. to GA & MS
Native Habitat: Thickets; pastures
Growing ConditionsWater 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.
BenefitUse Ornamental: Valued primarily for its silvery foliage, secondarily for its flowers.
Conspicuous Flowers: yes
Interesting Foliage: yes
Fragrant Foliage: yes
Nectar Source: yes
Deer Resistant: No
Value to Beneficial InsectsSpecial 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.
PropagationDescription: 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 DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Mt. Cuba Center - Hockessin, DE
BibliographyBibref 1620 - Gardening with Native Plants of the South (Reprint Edition) (2009) Wasowski, S. with A. Wasowski
Search More Titles in Bibliography
Web ReferenceWebref 34 - Go Botany (2019) Native Plant Trust
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter
Additional resourcesUSDA: Find Pycnanthemum incanum in USDA Plants
FNA: Find Pycnanthemum incanum in the Flora of North America (if available)
Google: Search Google for Pycnanthemum incanum
MetadataRecord Modified: 2023-02-23
Research By: TWC Staff