shrubby penstemon vs genus Penstemon

shrubby penstemon and genus Penstemon both are nouns.

Word	Noun	Adjective	Verb	Adverb
shrubby penstemon	Yes	No	No	No
genus Penstemon	Yes	No	No	No

shrubby penstemon (noun)	genus Penstemon (noun)
low bushy plant with large showy pale lavender or blue-violet flowers in narrow clusters at ends of stems	large genus of subshrubs or herbs having showy blue or purple or red or yellow or white flowers; mostly western North America