spice bush vs shrub

spice bush and shrub both are nouns.

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

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

spice bush: deciduous shrub of the eastern United States having highly aromatic leaves and bark and yellow flowers followed by scarlet or yellow berries
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of spice bush include bush.

spice bush (noun)	shrub (noun)
deciduous shrub of the eastern United States having highly aromatic leaves and bark and yellow flowers followed by scarlet or yellow berries	a low woody perennial plant usually having several major stems