Prepare to prune scuppernongs by sharpening and cleaning your pruning shears. Shears can be cleaned using a solution of 1 part bleach and 1 part water. Pruning will prevent the spread of disease and keep grapes healthy. Most grapevines are trained to a single vertical vine that is trellised to support at least two horizontal side vines called cordons.
In the dormant season, typically December through early February, cut back all growth that was produced on established vines during the current season to 4 to 5 inches long. Thin out the remaining 4-inch spurs so that they are 6 inches apart on young vines. As the vines age, they will develop clusters of these spurs. The spur clusters must be thinned every few years; otherwise, the plant will not develop new vines.
Remove any new shoots growing from the main cordon of the scuppernongs as well as any broken or damaged vines. The new shoots are known as suckers. They will steal nutrients and water from the vine and slow development of desirable vines and grapes.