pokeweed vs winterberry holly

pokeweed

noun
  • A poisonous North American plant, Phytolacca americana, with reddish stems, broad leaves, clusters of white flowers, and dark purple berries. 

winterberry holly

noun
  • American winterberry, Ilex verticillata. 

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