hogweed vs portulaca

hogweed

noun
  • Any coarse weedy herb. 

  • An umbelliferous plant, of genus Heracleum, most species of which are phototoxic. 

  • Certain plants from the genera Ambrosia, Erigeron, or Heracleum. 

portulaca

noun
  • Any of many tropical trailing herbs, of the genus Portulaca, having showy flowers 

  • Any plant in the genus Portulaca 

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