cranberry heath vs shrub

cranberry heath and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
cranberry heath	Yes	No	No	No
shrub	Yes	No	No	No

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

cranberry heath: small prostrate or ascending shrub having scarlet flowers and succulent fruit resembling cranberries; sometimes placed in genus Styphelia
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of cranberry heath include bush.

cranberry heath (noun)	shrub (noun)
small prostrate or ascending shrub having scarlet flowers and succulent fruit resembling cranberries; sometimes placed in genus Styphelia	a low woody perennial plant usually having several major stems