crystal tea vs shrub

crystal tea and shrub both are nouns.

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

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

crystal 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 crystal tea include bush.

crystal 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