American pokeweed vs hairy nightshade

American pokeweed

noun

  • Phytolacca americana, pokeweed. 

hairy nightshade

noun

  • Solanum physalifolium 

  • Solanum sarrachoides 

  • Solanum villosum 

How often have the words American pokeweed and hairy nightshade occurred in a corpus of books? (source: Google Ngram Viewer )