sage vs sage-green

sage is a noun but sage-green is not a noun.

Word	Noun	Adjective	Verb	Adverb
sage	Yes	Yes	No	No
sage-green	No	Yes	No	No

As adjectives, sage and sage-green are synonyms defined as:

sage (noun)	sage-green (noun)
aromatic fresh or dried grey-green leaves used widely as seasoning for meats and fowl and game etc
a mentor in spiritual and philosophical topics who is renowned for profound wisdom
any of various plants of the genus Salvia; a cosmopolitan herb

sage (adjective)	sage-green (adjective)
of the grey-green color of sage leaves	of the grey-green color of sage leaves
having wisdom that comes with age and experience