flower vs flowering plant

flower and flowering plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
flower	Yes	No	Yes	No
flowering plant	Yes	No	No	No

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

Other hypernyms of flower include angiosperm.

flower (noun)	flowering plant (noun)
a plant cultivated for its blooms or blossoms	plants having seeds in a closed ovary
reproductive organ of angiosperm plants especially one having showy or colorful parts
the period of greatest prosperity or productivity

flower (verb)	flowering plant (verb)
produce or yield flowers