perennial vs plant life

perennial and plant life both are nouns.

Word	Noun	Adjective	Verb	Adverb
perennial	Yes	Yes	No	No
plant life	Yes	No	No	No

As nouns, plant life is a hypernym of perennial; that is, plant life is a word with a broader meaning than perennial:

Other hypernyms of perennial include flora, plant.

perennial (noun)	plant life (noun)
(botany) a plant lasting for three seasons or more	(botany) a living organism lacking the power of locomotion

perennial (adjective)	plant life (adjective)
lasting three seasons or more
recurring again and again
lasting an indefinitely long time; suggesting self-renewal