Mentha pulegium

Mentha pulegium_pennyroyal JM Di Tomaso
Photo: Joseph DiTomaso

Synonyms: Mentha daghestanica Boriss.; Pulegium dagestanicum (Boriss.) Holub; Pulegium vulagare Mill.

Common names: pennyroyal; European pennyroyal; grows-in-a-ditch

Mentha pulegium (pennyroyal) is a perennial mint (family Lamiaceae) with a variable habit, ranging from low-growing, spreading plants to lanky, upright sub-shrubs. Although considered uncommon in much of California, pennyroyal occurs in the Sierra foothills, Central Valley, and most coastal counties from the Mexican border to Oregon. It is common as an obligate wetland indicator species in seasonally inundated soils of valley bottomlands, usually below 1,640 feet (500 m) elevation. Pennyroyal grows in flooded or seasonally wet areas: seeps, streamsides, vernal pools and swales, marshes, and ditches. Although pennyroyal is considered moderately invasive in wetlands its ecological impacts are not well documented. It clearly prospers in habitats that were once dominated by native plants, suggesting that it may have displaced some species. In particular, the flora of vernal pools may have suffered loss of habitat through the introduction of pennyroyal. It is native to Europe.

Cal-IPC Rating: Moderate?

CDFA Rating: None?


Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Species ID Card

Invasive Species ID Card - To support field identification of early detection species, Cal-IPC has designed a set of Species ID cards that can be downloaded, printed double-sided, and trimmed to size.

Weed Management Notes

  • Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

Other Mentha pulegium Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - Distribution map and records of this species in California.
  • CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
  • EDDMapS - Distribution of this species in North America.
  • Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.
  • Additional photos

    Mentha pulegium_inflorescence_copyright2007_NealKramer
    Mentha pulegium (pennyroyal) inflorescence. Photo: &#169 2007 Neal Kramer
    Mentha pulegium_leaves_copyright2010_NealKramer
    Mentha pulegium (pennyroyal) leaves. Photo: &#169 2010 Neal Kramer
    Mentha pulegium_infestation_copyright2012_NealKramer
    Mentha pulegium (pennyroyal) infestation. Photo: &#169 2012 Neal Kramer