Our customer brought in a vine w/leaves and a stem with a 2" diameter cluster of 1/8' - 1/4" dark, dark blue berries! The berry cluster is the shape of a perfect ball. . . bigger than a golf ball! Smaller than a tennis ball! Leaves are medium or kelly green color, not a deep green without any nodules in leaves just a simple shape. This customer says it grows about or at least an INCH A NIGHT!! I can provide pictures. We live in Chillicothe, Illinois - Zone 5. . . getting closer to Zone 6. Please help us identify and Thank You for your time.