strawberry bush vs shrub

strawberry bush and shrub both are nouns.

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

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

strawberry bush: upright deciduous plant with crimson pods and seeds; the eastern United States from New York to Florida and Texas
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of strawberry bush include bush.

strawberry bush (noun)	shrub (noun)
upright deciduous plant with crimson pods and seeds; the eastern United States from New York to Florida and Texas	a low woody perennial plant usually having several major stems
hardy shrub of southeastern United States having clove-scented wood and fragrant red-brown flowers