comfrey vs healing herb

comfrey and healing herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
comfrey	Yes	No	No	No
healing herb	Yes	No	No	No

As nouns, comfrey and healing herb are synonyms defined as:

comfrey and healing herb: leaves make a popular tisane; young leaves used in salads or cooked

comfrey (noun)	healing herb (noun)
leaves make a popular tisane; young leaves used in salads or cooked	leaves make a popular tisane; young leaves used in salads or cooked
perennial herbs of Europe and Iran; make rapidly growing groundcover for shaded areas