cascade penstemon vs wildflower

cascade penstemon and wildflower both are nouns.

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

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

cascade penstemon: whorls of deep blue to dark purple flowers at tips of erect leafy stems; moist places from British Columbia to Oregon
wildflower: wild or uncultivated flowering plant

Other hypernyms of cascade penstemon include wild flower.

cascade penstemon (noun)	wildflower (noun)
whorls of deep blue to dark purple flowers at tips of erect leafy stems; moist places from British Columbia to Oregon	wild or uncultivated flowering plant