western redbud vs shrub

western redbud and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
western redbud	Yes	No	No	No
shrub	Yes	No	No	No

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

western redbud: shrub of western United States having pink or crimson flowers; often forms thickets
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of western redbud include bush.

western redbud (noun)	shrub (noun)
shrub of western United States having pink or crimson flowers; often forms thickets	a low woody perennial plant usually having several major stems