witchgrass vs couch grass

witchgrass and couch grass both are nouns.

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

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

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

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

witchgrass (noun)	couch grass (noun)
North American grass with slender brushy panicles; often a weed on cultivated land	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