bitterweed vs famine weed

bitterweed

noun
  • Parthenium hysterophorus (false ragweed) 

  • The plant Helenium amarum (yellow sneezeweed). 

  • Any plant in the genus Ambrosia, especially Ambrosia artemisiifolia (common ragweed). 

  • Picris rhagadioloides (syn. Picris sprengeriana; tall oxtongue) 

  • Artemisia tripartita subsp. tripartita (syn. Artemisia trifida; threetip sagebrush) 

  • Tetraneuris spp. 

famine weed

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

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