bog hemp vs herb

bog hemp and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
bog hemp	Yes	No	No	No
herb	Yes	No	No	No

As nouns, herb is a hypernym of bog hemp; that is, herb is a word with a broader meaning than bog hemp:

bog hemp: any of several flowering weeds of the genus Boehmeria lacking stinging hairs
herb: a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests

Other hypernyms of bog hemp include herbaceous plant.

bog hemp (noun)	herb (noun)
any of several flowering weeds of the genus Boehmeria lacking stinging hairs	aromatic potherb used in cookery for its savory qualities
	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests