garden plant vs flora

garden plant and flora both are nouns.

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

garden plant: any of a variety of plants usually grown especially in a flower or herb garden
flora: (botany) a living organism lacking the power of locomotion

Other hypernyms of garden plant include plant, plant life.

garden plant (noun)	flora (noun)
any of a variety of plants usually grown especially in a flower or herb garden	all the plant life in a particular region or period
	(botany) a living organism lacking the power of locomotion