cudweed vs western mugwort

cudweed and western mugwort both are nouns.

Word	Noun	Adjective	Verb	Adverb
cudweed	Yes	No	No	No
western mugwort	Yes	No	No	No

As nouns, cudweed and western mugwort are synonyms defined as:

cudweed and western mugwort: perennial cottony-white herb of southwestern United States

Other synonyms of cudweed include Artemisia gnaphalodes, Artemisia ludoviciana, prairie sage, white sage.

cudweed (noun)	western mugwort (noun)
any of numerous plants of the genus Gnaphalium having flowers that can be dried without loss of form or color	perennial cottony-white herb of southwestern United States
any plant of the genus Filago having capitate clusters of small woolly flower heads
perennial cottony-white herb of southwestern United States