bloody dock vs red-veined dock

bloody dock

noun
  • A herb named for its characteristic red or purple veins, used in moderate amounts in salads and as ornamental vegetable, Rumex sanguineus. 

red-veined dock

noun
  • bloody dock, Rumex sanguineus 

How often have the words bloody dock and red-veined dock occurred in a corpus of books? (source: Google Ngram Viewer )