wax myrtle vs shrub

wax myrtle and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
wax myrtle	Yes	No	No	No
shrub	Yes	No	No	No

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

wax myrtle: any shrub or small tree of the genus Myrica with aromatic foliage and small wax-coated berries
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of wax myrtle include bush.

wax myrtle (noun)	shrub (noun)
any shrub or small tree of the genus Myrica with aromatic foliage and small wax-coated berries	a low woody perennial plant usually having several major stems