pocan vs woolly nightshade

pocan

noun
  • The poke, Phytolacca americana (formerly Phytolacca decandra). 

woolly nightshade

noun
  • Solanum mauritianum, a pest plant native to South America. 

  • Solanum villosum, a plant native to the Mediterranean. 

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