Lycopus virginicus aka Water Horehound

Lycopus virginicus is straightforward to grow where its moisture requirements are met. PFAF and Useful Temperate Plants both note it tolerates most soil types so long as they stay wet, and it accepts anything from partial shade to full sun. The main constraint is access to consistently moist or wetland conditions; without them the plant will not establish.

PFAF reports the species accepts light (sandy), medium (loamy) and heavy (clay) soils across mildly acidic, neutral and mildly alkaline pH. The common requirement across all sources is that the soil stays moist to wet — Useful Temperate Plants and Minnesota Wildflowers both stress that consistently damp ground (floodplains, swamp margins, pond and stream edges) is essential.

PFAF describes a typical wetland-perennial cycle: foliage emerges in spring, flowers from July through September (also reported by Minnesota Wildflowers), and the plant dies back over winter. Propagation by seed or division is recommended in spring or autumn.

Wikipedia notes that Virginia bugleweed carries a mint scent in the foliage, accompanied by a bitter taste — characteristic of its membership in the Lamiaceae family.

Flowers are tiny tubular blooms about 1/8 inch long, white and sometimes flushed pink, packed into dense whorls in the leaf axils. Each flower has four to five short lobes; the corolla is bell-shaped with one or two stamens that remain inside the tube. Bloom runs from July into September.

The infraspecific taxon Lycopus virginicus var. pauciflorus Benth. is listed by ITIS as not accepted. In the wild the species hybridises with Lycopus uniflorus to form Lycopus × sherardii.

Lycopus virginicus grows naturally along the shores of rivers and lakes, in swamps, floodplains, wet meadows and moist woodlands. It is an obligate wetland species and needs consistently wet ground. It tolerates partial shade to full sun and most soil textures so long as they remain damp. PFAF gives a USDA hardiness range of 4 to 8.

Both PFAF and Useful Temperate Plants recommend the same two methods: sow seed in spring or autumn in a cold frame, and divide established clumps in spring or autumn.

PFAF lists bees and flies as the principal pollinators, consistent with the small white tubular Lamiaceae flowers visible in the leaf axils.

Edibility is limited. PFAF and Useful Temperate Plants both rate the species 2 out of 5, with the cooked root the only documented edible part. Wikipedia cites the Native American Ethnobotany database recording that the Iroquois considered the plant poisonous, suggesting traditional caution rather than enthusiastic food use.

Lycopus virginicus has a long folk and herbal medicine history. Cherokee tradition recorded by Go Botany describes chewing the roots and giving them to infants to encourage "eloquence of speech." PFAF and Useful Temperate Plants list the whole plant as astringent, hypoglycaemic, mild narcotic, mild sedative and heart-strengthening, with use for overactive thyroid (including Graves' disease), rapid heartbeat, premenstrual symptoms, coughs and bleeding from the lungs. Wikipedia notes that "medical research has not validated the use of the herb for these conditions," and the species is not included in the NCCIH Herbs at a Glance series. The plant is known to enlarge the thyroid gland and is contraindicated in pregnancy, hypothyroidism and in patients on thyroid therapy.

PFAF rates other uses as 0 out of 5 and lists no non-food, non-medicinal applications for the species.

Water Horehound grows vertically and new growth emerges from the top of the plant.

Water Horehound’s native range is Eastern N. America - New York and Wisconsin south to Georgia and Texas.

Water Horehound should be watered regularly, allowing the soil to dry out between waterings.

To ensure optimal growth, the Water Horehound prefers bright diffused light for 6-8 hours each day. Insufficient light can result in slow growth and leaf drop, so it's important to find a well-lit location for this plant. Place it near a window, within a distance of 1 meter (3 feet), to enhance its potential for thriving.

Water Horehound is poisonous to humans if ingested. We suggest keeping this plant out of reach if you have children in the home.