rooibos vs shrub

rooibos and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
rooibos	Yes	No	No	No
shrub	Yes	No	No	No

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

rooibos: South African shrub having flat acuminate leaves and yellow flowers; leaves are aromatic when dried and used to make an herbal tea
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of rooibos include bush.

rooibos (noun)	shrub (noun)
South African shrub having flat acuminate leaves and yellow flowers; leaves are aromatic when dried and used to make an herbal tea	a low woody perennial plant usually having several major stems