celery vs shrub celery

celery

noun
  • The stalks of this herb eaten as a vegetable. 

  • A European herb (Apium graveolens) of the carrot family. 

  • A yellow-green colour, like that of a celery. 

shrub celery

noun
  • The crisp, thick leafstalk of the celery plant; used as a vegetable, or eaten raw. 

How often have the words celery and shrub celery occurred in a corpus of books? (source: Google Ngram Viewer )