Verbena triphylla and others vs lemon verbena

Verbena triphylla and others

lemon verbena

noun

  • A deciduous perennial shrub native to South America, used for its lemon-like fragrance and flavor, Aloysia citrodora. 

How often have the words Verbena triphylla and others and lemon verbena occurred in a corpus of books? (source: Google Ngram Viewer )