bastard pimpernel vs subshrub

bastard pimpernel and subshrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
bastard pimpernel	Yes	No	No	No
subshrub	Yes	No	No	No

As nouns, subshrub is a hypernym of bastard pimpernel; that is, subshrub is a word with a broader meaning than bastard pimpernel:

Other hypernyms of bastard pimpernel include suffrutex.

bastard pimpernel (noun)	subshrub (noun)
weedy plant having short dry chafflike leaves	low-growing woody shrub or perennial with woody base