In milder climates, it's easier to tell if a plant is dead in the winter. With only a modest challenge to remain green during a season that is merely chilly, not arctic, if the plant is brown, it's usually a goner. For plants in climates with more intense winters, this basic Green : Alive / Brown : Dead thinking must sometimes be tossed. Plants stay alive on their own terms, leaving the conceptual catch-up to us.
This is a large colony of wire vine—most often seen as a container annual, or a rampant but beautiful groundcover in Zones 8 and 9—that has been thriving for many years here in southern New England. The foliage of the upper reaches is green, while that of the lower is brown. For this plant in this site in this Zone 7a climate, its reality is Green : High / Brown : Low / Either Color, High or Low : Just Fine. What gives?