locoweed vs skunkweed

locoweed

noun
  • Any of several plants indigenous to the western United States, of genus Oxytropis or Astragalus. 

skunkweed

noun
  • Any of several American plants that have an offensive odour, but especially Croton texensis and Polemonium viscosum 

  • strong-smelling cannabis 

How often have the words locoweed and skunkweed occurred in a corpus of books? (source: Google Ngram Viewer )