Scuppernong is arguably the most well-known assortment of muscadine grape (Vitis rotundifolia) climbed through U. S. Department of Agriculture plant hardiness zones 6 through 9. This fast-growing, hardy native American grape is a great selection for home gardeners who need lots of big grapes for making juice, jelly or wine. Even though they require less maintenance than bunching grapes, muscadines have to be pruned aggressively to keep them in perfect shape — also much old timber is detrimental to fruit production.
Prune a newly planted muscadine grape to a major stem with no more than two or three buds emerging from it. Allow the plant to climb to the very top of its support the first year, removing all but the strongest length of vine once it goes dormant in the late fall or early winter. Remove any portion of the major vine that reaches over a few inches past the cover of the wire at dormancy, to induce the formation of unwanted shoots.
Allow new buds to develop on surface of your vine at a 90-degree angle from the main back during the next season. Select the best two to four buds, depending upon your trellis style, and get rid of the remainder as soon as they are approximately 2 inches long. Remove any buds that develop below the top of your grape trellis or so are clustered close to other buds. Allow both to four sections you kept to develop along the surface of the trellis in various directions to their entire length during the next season.
Thin the buds that form along the lateral parts of the vine in the preceding year to no longer than approximately six, spaced evenly along the length of every section, early in the spring of the next season. At the close of the season, remove these six sections of vine to support fruiting the following year — muscadines fruit only on new wood, so these old fruiting canes are a naturally drag on the plant’s sources. Continue removing fruiting canes at the end of each growing season for the life of the muscadine vine.