bloodroot vs yarrow

bloodroot

noun
  • A North American plant, Sanguinaria canadensis, of the poppy family, which has a red root and sap and a single white flower in early spring. 

yarrow

noun
  • Common yarrow, Achillea millefolium, the type species of the genus. 

  • The green woodpecker, Picus viridis. 

  • Any of several pungent Eurasian and North American herbs, of the genus Achillea, used in traditional herbal medicine. 

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