Mentha x piperita L.

Description

Perennial plant with wide-spreading rhizomes.
Sterile hybrid from cross between watermint (Mentha aquatica) and spearmint (Mentha spicata).
Indigenous to Europe and the Middle East. Now widespread in cultivation in many regions of the world.
For commercial production, long midsummer days, full sun, and significant day/night temperature fluctuations are desirable (typically north of the 40^th parallel).
Major growing areas are the USA (Pacific Northwest (~3,000 tons/year) and Midwest (~ 350 tons/year)), China, England, France, India, Italy, and Japan.
Clonally propagated.
Most devastating pathogen in commercial peppermint production is Verticillium dahliae (causes Verticillium wilt disease).

Genetics

2n=6x=72 (Mentha x piperita L. cv. Black Mitcham).

Oil characteristics

High: (-)-menthone, (-)-menthol.
Low: (+)-menthofuran, 1,8-cineole, (-)-menthyl acetate.

Notes The re-creation of peppermint from putative ancestral cultivars has thus far been unsuccessful.

Essential oil composition of peppermint (Mentha x piperita) from Yakima Valley growing area (Washington State, USA):

Constituent	Abundance (% of oil)	Structure
(-)-Menthol	37-47
(-)-Menthone	15-21
(+)-Menthofuran	5-8
1,8-Cineole	4-6
(-)-Menthyl acetate	4-6
(+)-Neomenthol	3-5
(+)-Isomenthone	2-3
β-Caryophyllene	1-3
(-)-Limonene	1-3
Germacrene D	1-3
α-Terpineol	1-2

Minor constituents (between 0.5 and 1.5 %): myrcene, α-pinene, β-pinene, sabinene, α-terpinene, γ-terpinene, (+)-neoisomenthol, β-farnesene. About 10-15 other constituents are generally detectable at below 0.5 %.

References

B.M. Lawrence (Ed.) (2006) Mint - The Genus Mentha, CRC Press.
Murray M.J.L., Lincoln, D.E., Marble, P.M. (1972) Oil composition of Mentha aquatica x M. spicata F1 hybrids in relation to the origin of M. x piperita. Can. J. Genet. Cytol. 14: 13-29.