plant vs perennial

plant and perennial both are nouns.

As nouns, perennial is a hyponym of plant; that is, perennial is a word with a more specific, narrower meaning than plant:

Other hyponyms of plant include microflora, crop, endemic, holophyte, non-flowering plant, plantlet, wilding, ornamental, pot plant, acrogen, apomict, aquatic, cryptogam, annual, biennial, escape, hygrophyte, neophyte, embryo, monocarp, monocarpic plant, monocarpous plant, sporophyte, gametophyte, houseplant, garden plant, vascular plant, tracheophyte, poisonous plant, epiphyte, epiphytic plant, aerophyte, air plant, rock plant, autophyte, autophytic plant, autotroph, autotrophic organism, myrmecophyte, phytoplankton.

plant (noun)	perennial (noun)
buildings for carrying on industrial labor	(botany) a plant lasting for three seasons or more
(botany) a living organism lacking the power of locomotion
an actor situated in the audience whose acting is rehearsed but seems spontaneous to the audience
something planted secretly for discovery by another

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

plant (verb)	perennial (verb)
put or set (seeds, seedlings, or plants) into the ground
fix or set securely or deeply
set up or lay the groundwork for
place into a river
place something or someone in a certain position in order to secretly observe or deceive
put firmly in the mind