purple loco vs crazy weed

purple loco and crazy weed both are nouns.

Word	Noun	Adjective	Verb	Adverb
purple loco	Yes	No	No	No
crazy weed	Yes	No	No	No

As nouns, crazy weed is a hypernym of purple loco; that is, crazy weed is a word with a broader meaning than purple loco:

purple loco: tufted locoweed of southwestern United States having purple or pink to white flowers
crazy weed: any of several leguminous plants of western North America causing locoism in livestock

Other hypernyms of purple loco include crazyweed, locoweed.

purple loco (noun)	crazy weed (noun)
tufted locoweed of southwestern United States having purple or pink to white flowers	any of several leguminous plants of western North America causing locoism in livestock