lavender vs shrub

lavender and shrub both are nouns.

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

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

lavender: any of various Old World aromatic shrubs or subshrubs with usually mauve or blue flowers; widely cultivated
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of lavender include bush.

lavender (noun)	shrub (noun)
a pale purple color	a low woody perennial plant usually having several major stems
any of various Old World aromatic shrubs or subshrubs with usually mauve or blue flowers; widely cultivated

lavender (adjective)	shrub (adjective)
of a pale purple color