Lycopus americanus aka American Bugleweed

Lycopus americanus is a perennial in the mint family, Lamiaceae. Gardeners know it as water horehound or water bugle. Its native range spans Canada and the United States. It grows in temperate regions across much of North America. It is not native to Britain or Ireland. Wild plants grow in low ground with moist or wet soil. These sites help explain its need for steady soil moisture.

The plant has an upright form and reaches about 1.6 feet (0.5 metres). Small white flowers form tight groups at the leaf axils. Each tubular flower measures about one-eighth of an inch across. The blooms are modest rather than bold garden features. Plants For A Future lists flowering from July to September. Chicago Botanic Garden extends the season through October. Each flower has both male and female organs. Bees and flies pollinate the flowers. The fruit consists of four nutlets arranged in a square. Each nutlet holds one seed.

Grow water horehound in full sun or partial shade. It suits damp meadows and wet ground beside ponds or streams. A bog garden offers another suitable setting. It accepts sandy soil, loam, and clay. Soil can range from mildly acid to mildly alkaline. Keep the soil moist or wet to match its growing needs. Chicago Botanic Garden lists USDA hardiness zones 3–11. It also lists the plant for beds and borders. Its small flowers offer less visual impact than its upright form.

Plants For A Future lists seed sowing in spring or autumn. It recommends a cold frame for this stage. Young seedlings can spend their first year under greenhouse cover. Plant them out in early summer. Clumps can also be split in spring or autumn. Large divisions can go straight into their final site. Smaller pieces benefit from time in pots while roots develop. The same source flags weed potential, so allow for unwanted spread.

Plants For A Future reports raw or cooked roots as edible. It gives edibility a low score and notes conflicting reports about tubers. This leaves some doubt around the reported food use. Plant juice has also served as a lasting fabric dye. The source records medicinal uses, including effects on blood sugar and heart contractions. It warns against medicinal use during pregnancy or with an underactive thyroid. Its report of no known hazards does not establish general safety.