Lycopus virginicus
Virginia water-horehound
Image of Lycopus virginicus

Photo by Bradford S. Slaughter 

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Key Characteristics

Medium-sized forb of floodplain forests; stem without a tuberous base as in the similar-looking L. uniflorus; leaves elliptic and coarsely serrate; flowers tiny and white; fruits a set of four tiny nutlets (each 1.5-2 mm long), with tiny (1 mm) triangular calyx lobes not longer than the nutlets.

Status and Rank

  • State Status: T
  • State Rank: S2
  • Global Rank: G5


County NameNumber of OccurrencesYear Last Observed
Distribution map for Lycopus virginicus

Updated 5/15/2018. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Virginia water-horehound is locally common in first and second bottoms of floodplain forests, particularly along the Red Cedar River in Ingham County and the River Raisin in Lenawee County.

Natural Community Types


For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Associated Plants

Trees: Acer saccharinum (silver maple), Celtis occidentalis (hackberry), Fraxinus pennsylvanica (green ash), Populus deltoides (cottonwood), Salix nigra (black willow), Ulmus americana (American elm).

Shrubs and Vines: Cephalanthus occidentalis (buttonbush), Parthenocissus quinquefolia (Virginia creeper), Toxicodendron radicans (poison-ivy), Vitis riparia (riverbank grape).

Herbs: Arisaema dractonium (green dragon), Carex grayi, C. grisea, C. lupulina, C. muskingumensis, C. stipata, Cinna arundinacea (wood reedgrass), Elymus riparius (riverbank wild-rye), E. virginicus (Virginia wild-rye), Iris virginica (southern blue flag), Laportea canadensis (wood nettle), Leersia virginica (white grass), Onoclea sensibilis (sensitive fern), Persicaria virginiana (jumpseed), Pilea pumila (clearweed), Rumex verticillatus (water dock), Saururus cernuus (lizard's-tail), Scutellaria lateriflora (mad-dog skullcap), Symphyotrichum lateriflorum (calico aster), Teucrium canadense (wood sage), Verbena urticifolia (white vervain).


Primarily requires protection of habitat and maintenance of riparian hydrological regime. Possibly sensitive to excessive timber harvesting and river pollution.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgment of the investigator.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Sep 24, 2018]

More Information

See MNFI Species Abstract


Survey References

Technical References

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