nurseryman vs horticulturist

nurseryman and horticulturist both are nouns.

Word	Noun	Adjective	Verb	Adverb
nurseryman	Yes	No	No	No
horticulturist	Yes	No	No	No

As nouns, horticulturist is a hypernym of nurseryman; that is, horticulturist is a word with a broader meaning than nurseryman:

nurseryman: someone who takes care of a garden
horticulturist: an expert in the science of cultivating plants (fruit or flowers or vegetables or ornamental plants)

Other hypernyms of nurseryman include plantsman.

nurseryman (noun)	horticulturist (noun)
someone who takes care of a garden	an expert in the science of cultivating plants (fruit or flowers or vegetables or ornamental plants)