undergrown vs undeveloped

undergrown

adj
  • insufficiently grown; not having grown to a normal or suitable size. 

undeveloped

adj
  • not developed or used 

  • not built on, unbuilt; not ready for building on 

  • lagging behind others, especially in economic or social matters 

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