witch grass vs couch grass

witch grass and couch grass both are nouns.

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

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

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

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

witch grass (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