Crossword clue: a species of mint (mentha viridis) growing in moist soil. it vields an aromatic oil. see mint, and mentha.
1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
common garden herb having clusters of small purplish flowers and yielding an oil used as a flavoring