quackgrass vs couch grass

quackgrass and couch grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
quackgrass	Yes	No	No	No
couch grass	Yes	No	No	No

As nouns, quackgrass and couch grass are synonyms defined as:

quackgrass and couch grass: European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed

Other synonyms of quackgrass include Agropyron repens, dog grass, quack grass, quick grass, witch grass, witchgrass.

quackgrass (noun)	couch grass (noun)
European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed	European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed