bloodwort vs old man's pepper

bloodwort

noun
  • Sanguinary, common yarrow, Achillea millefolium. 

  • Rumex sanguineus, bloody dock, wood dock, bloody-veined dock. 

  • Capsella bursa-pastoris, shepherd's purse. 

  • Any of the Haemodoraceae, a family of flowering plants some of whose roots contain a red dye. 

  • The plant bloodroot, Sanguinaria canadensis. 

  • Various species in the genus Sanguisorba, burnet. 

old man's pepper

noun
  • Achillea millefolium or common yarrow, a flowering plant native to temperate regions of the Northern Hemisphere. 

How often have the words bloodwort and old man's pepper occurred in a corpus of books? (source: Google Ngram Viewer )