garden pea vs green pea

garden pea and green pea both are nouns.

Word	Noun	Adjective	Verb	Adverb
garden pea	Yes	No	No	No
green pea	Yes	No	No	No

As nouns, garden pea and green pea are synonyms defined as:

garden pea (noun)	green pea (noun)
fresh pea	fresh pea
plant producing peas usually eaten fresh rather than dried
the flattened to cylindric inflated multi-seeded fruit of the common pea plant