cow parsley vs herbaceous plant

cow parsley and herbaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
cow parsley	Yes	No	No	No
herbaceous plant	Yes	No	No	No

As nouns, herbaceous plant is a hypernym of cow parsley; that is, herbaceous plant is a word with a broader meaning than cow parsley:

cow parsley: coarse erect biennial Old World herb introduced as a weed in eastern North America
herbaceous plant: a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests

Other hypernyms of cow parsley include herb.

cow parsley (noun)	herbaceous plant (noun)
coarse erect biennial Old World herb introduced as a weed in eastern North America	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests