flame bush vs shrub

flame bush and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
flame bush	Yes	No	No	No
shrub	Yes	No	No	No

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

flame bush: Australian shrub having simple obovate leaves and brilliant scarlet flowers
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of flame bush include bush.

flame bush (noun)	shrub (noun)
Australian shrub having simple obovate leaves and brilliant scarlet flowers	a low woody perennial plant usually having several major stems