Winter is the season of cold weather, delicate snow, and icy rains. While winter is many things, a growing season it is not. So what exactly happens to grapevines in the winter? After grapes have been harvested in autumn, leaves begin to fall away and the vines die off growing hard and woody like the trunk of the plant. Leaves continue to fall throughout the rest of the season until they are all gone, and the vines grow harder and harder until the plant looks completely dead.