flowering hazel vs shrub

flowering hazel and shrub both are nouns.

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

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

flowering hazel: any of several Asiatic deciduous shrubs cultivated for their nodding racemes of yellow flowers that appear before the leaves
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of flowering hazel include bush.

flowering hazel (noun)	shrub (noun)
any of several Asiatic deciduous shrubs cultivated for their nodding racemes of yellow flowers that appear before the leaves	a low woody perennial plant usually having several major stems