Spanish moss vs maiden's honesty

Spanish moss

noun
  • A gray epiphyte that hangs down from trees, Tillandsia usneoides, native to the southeastern US and throughout humid tropical and subtropical parts of the Americas. 

maiden's honesty

noun
  • A plant of the species Clematis vitalba, evergreen clematis, a vine, native to the chalk and limestone soils of Britain, often considered invasive and noxious elsewhere. 

How often have the words Spanish moss and maiden's honesty occurred in a corpus of books? (source: Google Ngram Viewer )