The Collaborative International Dictionary of English v.0.48:

Plantage \Plant"age\, n.
   A word used once by Shakespeare to designate plants in
   general, or anything that is planted.
   [1913 Webster]

         As true as steel, as plantage to the moon. --Shak.
                                                  (Troil. iii.
                                                  sc. 2).
   [1913 Webster]