Hedge False Bindweed or Hedge Bindweed [Calystegia sepium] found off Campbell Road in Hermon, New York, near Trout Lake, on 23 June 2013. It’s a member of the Morning Glory (Convolvulaceae) family. Newcomb’s Wildflower Guide, pages 324-325, which lists it as Convolvulus sepium states that it’s found in summer and fall in moist thickets.
USDA Plants Listing: https://plants.usda.gov/home/plantProfile?symbol=CASES