love-lies-bleeding vs velvet flower

love-lies-bleeding

noun
  • A tropical plant, Amaranthus caudatus, that has clusters of little red flowers 

velvet flower

noun
  • Amaranthus caudatus, an annual flowering plant, the love-lies-bleeding. 

How often have the words love-lies-bleeding and velvet flower occurred in a corpus of books? (source: Google Ngram Viewer )