Polemonium viscosum vs skunkweed

Polemonium viscosum

skunkweed

noun
  • strong-smelling cannabis 

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

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