The Collaborative International Dictionary of English v.0.48:

Verdure \Ver"dure\, n. [F., fr. L. viridis green. See
   Verdant.]
   Green; greenness; freshness of vegetation; as, the verdure of
   the meadows in June.
   [1913 Webster]

         A wide expanse of living verdure, cultivated gardens,
         shady groves, fertile cornfields, flowed round it like
         a sea.                                   --Motley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

verdure
    n 1: green foliage [syn: greenery, verdure]
    2: the lush appearance of flourishing vegetation [syn:
       greenness, verdancy, verdure]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "verdure":
   botany, chloranemia, chloremia, chlorophyll, chlorosis, flora,
   flowerage, glaucescence, glaucousness, green, greenery,
   greenishness, greenness, greens, greensickness, herbage, leafage,
   plant kingdom, plant life, plants, umbrage, vegetable kingdom,
   vegetable life, vegetation, vegetation spirit, verdancy,
   virescence, viridity