Labrador tea vs shrub

Labrador tea and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Labrador tea	Yes	No	No	No
shrub	Yes	No	No	No

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

Labrador tea: evergreen shrub of eastern North America having white or creamy bell-shaped flowers and dark green hairy leaves used for tea during American Revolution
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of Labrador tea include bush.

Labrador tea (noun)	shrub (noun)
evergreen shrub of eastern North America having white or creamy bell-shaped flowers and dark green hairy leaves used for tea during American Revolution	a low woody perennial plant usually having several major stems