At the time of harvest, or shortly thereafter, the vines begin to shut down. The leaves become vibrant colors of reds and yellows. In October and November the vineyards of Napa Valley are a patchwork quilt of beautiful colors. By Mid December all the leaves have fallen and the vines are dormant. From then until springtime, when they begin to bud, they will not be negatively affected by frost or rain. This is a time when the vines get a well deserved rest.