common yarrow vs milfoil

common yarrow

noun
  • Achillea millefolium, a flowering plant widespread in the temperate Northern Hemisphere, formerly and sometimes used to stanch the flow of blood. 

milfoil

noun
  • Common yarrow, Achillea millefolium. 

  • Any of several similar pungent Eurasian herbs, of the genus Achillea 

  • Any plants of the genus Myriophyllum; water milfoil. 

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