horseweed vs prince's feather

horseweed

noun
  • A plant of the species Cichorium intybus 

  • Any of various flowering plants of the genus Conyza. 

prince's feather

noun
  • Amaranthus hypochondriacus, an ornamental plant. 

How often have the words horseweed and prince's feather occurred in a corpus of books? (source: Google Ngram Viewer )