Oswego tea vs lemon balm

Oswego tea

noun
  • An American aromatic herb (Monarda didyma) with bright red labiate flowers. 

lemon balm

noun
  • A perennial herb, Melissa officinalis, of southern Europe; used as a flavouring in ice cream etc. 

How often have the words Oswego tea and lemon balm occurred in a corpus of books? (source: Google Ngram Viewer )