dog mercury vs herbaceous plant

dog mercury and herbaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
dog mercury	Yes	No	No	No
herbaceous plant	Yes	No	No	No

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

dog mercury: European perennial weedy plant with greenish flowers
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 dog mercury include herb.

dog mercury (noun)	herbaceous plant (noun)
European perennial weedy plant with greenish flowers	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests