poinciana vs flowering shrub

poinciana and flowering shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
poinciana	Yes	No	No	No
flowering shrub	Yes	No	No	No

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

poinciana: a tropical flowering shrub having bright orange or red flowers; sometimes placed in genus Poinciana
flowering shrub: shrub noted primarily for its flowers

poinciana (noun)	flowering shrub (noun)
a tropical flowering shrub having bright orange or red flowers; sometimes placed in genus Poinciana	shrub noted primarily for its flowers