Plumbago europaea vs shrub

Plumbago europaea and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Plumbago europaea	Yes	No	No	No
shrub	Yes	No	No	No

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

Other hypernyms of Plumbago europaea include bush.

Plumbago europaea (noun)	shrub (noun)
a plant of the genus Plumbago with blue flowers	a low woody perennial plant usually having several major stems