monocarpous plant vs plant life

monocarpous plant and plant life both are nouns.

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

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

Other hypernyms of monocarpous plant include flora, plant.

monocarpous plant (noun)	plant life (noun)
a plant that bears fruit once and dies	(botany) a living organism lacking the power of locomotion