Its leaves are oval, and dark and smooth, with serrated edges. It blossoms with light purple flowers throughout the summer.
It likes to grow in land under cultivation or in disturbed areas. It was called “Corn Mint” because it was a common “weed” in fields where cereal crops are grown.
It is less sweet than other mints, but has more menthol. Consequently, it is used a great deal to make commercial menthol flavouring extracts. It is steamed while it is in its flowering stage to help extract its oil, which before refining will be 60 to 80% menthol.
Corn Mint is cultivated in Argentina; Brazil; China; India; Japan; South Africa; and Taiwan.
Even though many of its synonyms refer to it as an Asian mint, it was present in Ireland in the Middle Ages, as archaeological digs of Dublin have shown.