water mint vs Mentha aquatica

water mint and Mentha aquatica both are nouns.

Word	Noun	Adjective	Verb	Adverb
water mint	Yes	No	No	No
Mentha aquatica	Yes	No	No	No

As nouns, water mint and Mentha aquatica are synonyms defined as:

water mint and Mentha aquatica: a European mint that thrives in wet places; has a perfume like that of the bergamot orange; naturalized in eastern North America

Other synonyms of water mint include water-mint.

water mint (noun)	Mentha aquatica (noun)
a European mint that thrives in wet places; has a perfume like that of the bergamot orange; naturalized in eastern North America	a European mint that thrives in wet places; has a perfume like that of the bergamot orange; naturalized in eastern North America