Mentha pulegium L., Lamiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Pulegium vulgare Mill.

Common name(s): [more details]

Chinese: chun e bo he

English: European pennyroyal, pennyroyal, peppermint

French: herbe aux puces, menthe pouliot, pouliot

Japanese: megusa hakka, penirooyaru minto

Spanish: menta, menta poleo, poleo

Habit:  herb

Description:  "Aromatic, tomentose perennial herbs; stems procumbent to ascending, 1-4 dm long.  Leaves narrowly ovate to narrowly elliptic, 8-30 mm long, 0.4-12 mm wide, pubescent at least on lower surface, margins subentire or with up to 6 teeth on each side, base attenuate, sessile or subsessile.  Flowers in well-spaced verticillasters in the leaf axils; calyx (2-) 2.5-3 mm long, the teeth ciliate, lower ones subulate, upper ones slightly shorter and wider; corolla lilac, (4-) 4.5-6 mm long; stamens exserted beyond to included in corolla tube.  Nutlets pale brown, ca. 0.7-0.8 mm long"  (Wagner et al., 1999; p. 807).

Habitat/ecology:  "Grassland, riparian habitats, freshwater wetlands, alluvial plains.  A highly variable species with regard to growth habit and leaf shape.  Several varieties have been described in the native range where it hybridizes with several congeners.  The plant forms dense stands that crowd out native vegetation and reduce species richness.  Damaged plants easily resprout"  (Weber, 2003; p. 266).

In Hawai‘i, "cultivated and escaping from gardens, usually in damp areas"  (Wagner et al., 1999; p. 807).  "In Chile this species grows in the following environmental conditions:  Low altitude, interior valleys; coastal mountains, 500-2000 m; coastal areas, 0-500 m.  Humid areas, with almost constant rainfall, short dry periods are possible (generally not longer than 1 month); somewhat dry areas where the drought may last 3-5 months, precipitations of 400-800 mm. are concentrated in winter.  Fully exposed to the sun, level areas or slopes facing north"  (Chileflora).

Propagation:  Seed.  "It is a prolific seed producer, and seeds are dispersed by water and animals.  Seedlings can emerge and establish under water, enabling the plant to invade flooded areas.  It accumulates a soil seed bank"  (Weber, 2003; p. 266).

Native range:  Northern Africa, Europe, western Asia; cultivated and naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 555)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced	Skottsberg, Carl (1953) (p. 223)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 555)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island		Bishop Museum (U.S.A. Hawaii. Honolulu.) (1948) (voucher ID: BISH 53279) Taxon name on voucher: Mentha pulegium L.
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 807) Voucher cited: Forbes 2633.M (BISH) Cultivated and escaping from gardens.
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced cultivated	MacKee, H. S. (1994) (p. 69) Voucher cited: MacKee 34795

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	New South Wales	introduced invasive	Porcher, Michel H. (2013) "Grows in damp areas, depressions, in alluvial silt of rivers, and on banks of rivers and creeks, occurring in sandy to loam-rich soils." Naturalised
Australia Australia (continental)	Australia (continental)	introduced invasive	Porcher, Michel H. (2013) South Australia, Tasmania, Victoria Naturalised
Australia Australia (continental)	Queensland	introduced invasive	Porcher, Michel H. (2013) Naturalised
British Columbia (province of Canada) Province of British Columbia	Canada (British Columbia)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
China China	China (People's Republic of)	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Beijing Shi, Nanjing Shi, and other cities.
Indonesia Indonesia	Indonesia (Republic of)	introduced cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013) Java
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 188)
Mexico Mexico	Mexico (United Mexican States)	introduced cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive cultivated	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 780) "Common to abundant in wet pastures, by rivers and lakesides, also in drier places, including bare lava and backs of sandy beaches".
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced	Skottsberg, Carl (1953) (p. 223)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive	Belov, Michail (2013)
United States (west coast) United States (west coast states)	USA (Oregon)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013) Maryland, New Jersey, Pennsylvania

Control: 

Physical:  "Single plants and small patches are hand pulled or dug out.  Roots and stolons must be removed to prevent regrowth.  Follow-up programs are necessary to treat regrowth and seedlings".

Chemical:  "Seedlings can be controlled with 2,4-D, established plants with glyphosate, metsulfuron-methyl, or triclopyr plus picloram"  (Weber, 2003; p. 266).