milfoil vs thousand-leaf

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. 

thousand-leaf

noun
  • Achillea millefolium or common yarrow, a flowering plant widespread in the temperate Northern Hemisphere, featuring finely divided leaves. 

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