famine weed vs feverfew

famine weed

noun
  • A plant of the species Parthenium hysterophorus, native to Central America, considered invasive in Africa, India, Australia 

feverfew

noun
  • A European aromatic perennial herb, Tanacetum parthenium (or Chrysanthemum parthenium or Pyrethrum parthenium), having daisy-like flowers; valued as a traditional medicine, especially for headaches. 

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