hemp willow vs osier

hemp willow and osier both are nouns.

Word	Noun	Adjective	Verb	Adverb
hemp willow	Yes	No	No	No
osier	Yes	No	No	No

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

hemp willow: willow with long flexible twigs used in basketry
osier: any of various willows having pliable twigs used in basketry and furniture

hemp willow (noun)	osier (noun)
willow with long flexible twigs used in basketry	any of various willows having pliable twigs used in basketry and furniture
	flexible twig of a willow tree