dandelion green vs greens

dandelion green and greens both are nouns.

Word	Noun	Adjective	Verb	Adverb
dandelion green	Yes	No	No	No
greens	Yes	No	No	No

As nouns, greens is a hypernym of dandelion green; that is, greens is a word with a broader meaning than dandelion green:

dandelion green: edible leaves of the common dandelion collected from the wild; used in salads and in making wine
greens: any of various leafy plants or their leaves and stems eaten as vegetables

Other hypernyms of dandelion green include green, leafy vegetable.

dandelion green (noun)	greens (noun)
edible leaves of the common dandelion collected from the wild; used in salads and in making wine	any of various leafy plants or their leaves and stems eaten as vegetables
the foliage of the dandelion plant