The fragrant minty leaves of this plant can be used in your dinner, but I prefer it to leave it in the garden where lots of bees and other pollinators can be found on the flowers. The tiny white flowers, upon close inspection, are covered in little purple polka dots. This delightful flower is a must have in your native plant garden, and it tolerates a wide range of light, soil and moisture conditions. As usual, the Plant Description and In the Garden sections, below, are courtesy of Shaun Booth from In Our Nature. This Plant of the Month article has been adapted from our book The Gardener’s Guide to Native Plants of the Southern Great Lakes Region.
Common Name: Virginia Mountain Mint
Scientific Name: Pycnanthemum virginianum
Family: Lamiaceae (Mint Family)
Alternate Common Names: American Mountain Mint, Common Mountain Mint, Mountain Mint, Mountain Thyme, Pennyroyal, Prairie Hyssop, Virginia Thyme, Wild Basil, Wild Hyssop
Plant description: Virginia Mountain Mint is a bushy plant with frequently branching stems that are 4-angled, green to reddish in colour and have scattered hairs along the edges. Opposite, stalkless leaves are found along the stem, the largest of which measure up to 6cm long and 1cm wide. Each leaf is toothless, hairless and has a pointed tip and rounded base. Stems terminate with numerous flat clusters of densely packed, tubular flowers. Each flower is small, at about 0.6cm wide, and features an upper lip with 2 lobes and a lower lip with 3 lobes. The upper lips often look like one lip. Both lips are white with purple spots. Flowers each mature into a dry capsule that holds 4 tiny, black seeds.
Similar to Slender Mountain Mint (Pycnanthemum tenuifolium) which has smooth stems and narrower leaves.
In the Garden: There are many reasons to love Virginia Mountain Mint including its copious, long-lasting blooms to its persistent seed heads that provide excellent winter interest. The minty foliage not only smells delightful but is rarely, if ever, bothered by browsing herbivores.
Skill level: beginner
Lifespan: perennial
Exposure: full sun to part shade
Soil Type: sand, clay, loam
Moisture: medium to moist to wet
Height: 75-90 cm
Spread: 30-45 cm
Bloom Period: Jul, Aug, Sep
Colour: white with purple
Fragrant (Y/N): Y (leaves)
Showy Fruit (Y/N): N
Cut Flower (Y/N): Y
Pests: no serious insect or disease problems, though stressed plants are susceptible to rust
Natural Habitat: mesic to wet prairies, edges of streams, marshes and sedge meadows
Wildlife value: typical visitors include honeybees, and a wide variety of native bees, beetles, and seems to be a favourite of Pearl Cresecent (Phyciodes tharos) butterflies
Butterfly Larva Host Plant For: none
Moth Larva Host Plant For: none
USDA Hardiness Zone: 3-7
Propagation: No pretreatment of seeds is necessary, but the tiny seeds need light to germinate so simply press into the soil in spring. Easily propagated by tip cuttings taken in June, or by lifting the clump in late fall or early spring and dividing.
Additional Info: Tolerates flooding early in the growing season only. Drought tolerant. Can be an aggressive spreader but is less so in drier soil.
Native Range:
