black alder winterberry vs pigeonweed

black alder winterberry

noun
  • A deciduous holly shrub, Ilex verticillata, native to eastern North America, growing best in moist circumstances. 

pigeonweed

noun
  • Synonym of pokeweed (“the plant Phytolacca americana”) 

How often have the words black alder winterberry and pigeonweed occurred in a corpus of books? (source: Google Ngram Viewer )