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.Cal-IPC Rating: Moderate
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
- Don’t sell a pest: A new partnership to prevent plant invasions through horticulture. Connick, Sarah; Gerel, Mike. Vol 13, Issue 2
- Highways as corridors of dispersal. Madison, John. Vol 04, Issue 1
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.
- Does horse manure harbor invasive plants? Quinn, Lauren; Davis, Bonnie; Kolipinski, Mietek; Ghosh, Sibdas (2006)
- Partnering to prevent invasions of plants of horticultural origin. Connick, Sarah; Gerel, Mike (2004)
Other Mentha pulegium Information
- CalPhotos - Images of plants taken mostly in California.
- Calflora - See the distribution of this species on Calflora's map of California.
- CalWeedMapper - Distribution information with ability to determine regional priorities.
- Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
- USDA PLANTS Database - Federal database with information on identification and distribution, and links to websites in individual states.
- EDD MapS - North American distribution based on Early Detection and Distribution Mapping System.