rock penstemon vs wildflower

rock penstemon and wildflower both are nouns.

Word	Noun	Adjective	Verb	Adverb
rock penstemon	Yes	No	No	No
wildflower	Yes	No	No	No

As nouns, wildflower is a hypernym of rock penstemon; that is, wildflower is a word with a broader meaning than rock penstemon:

rock penstemon: one of the West's most beautiful wildflowers; large brilliant pink or rose flowers in many racemes above thick mats of stems and leaves; ledges and cliffs from Washington to California
wildflower: wild or uncultivated flowering plant

Other hypernyms of rock penstemon include wild flower.

rock penstemon (noun)	wildflower (noun)
one of the West's most beautiful wildflowers; large brilliant pink or rose flowers in many racemes above thick mats of stems and leaves; ledges and cliffs from Washington to California	wild or uncultivated flowering plant