mountain grape vs shrub

mountain grape and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain grape	Yes	No	No	No
shrub	Yes	No	No	No

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

mountain grape: ornamental evergreen shrub of Pacific coast of North America having dark green pinnate leaves and racemes of yellow flowers followed by blue-black berries
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of mountain grape include bush.

mountain grape (noun)	shrub (noun)
ornamental evergreen shrub of Pacific coast of North America having dark green pinnate leaves and racemes of yellow flowers followed by blue-black berries	a low woody perennial plant usually having several major stems