Popular in the southeastern United States and in California, muscadine grapes are hardy growers capable of reaching 60 to 100 feet. The secret to maintaining a healthy backyard muscadine grape vine is rigorous annual pruning and trellising. Gardeners will spend four years establishing the main structure of a main trunk with two sets of arms and fruiting spurs. Thereafter, gardeners can prune the plant back to this basic structure, and the grape vine will produce significant new growth each year.
Leave the most powerfully growing shoot alone and prune away all competing shoots immediately after planting your muscadine grape vine. This establishes the central leader. Allow the shoot to grow until the following year.
Remove all competing shoots again in the second year. If the vine is long enough to reach the wire or wooden trellis, tether it to the trellis with twine and cut it off just above the trellis using hand pruners. Allow the plant to develop shoots until the new shoots average 1 to 3 inches in length.
Leave three to four of these offshoots from the main vine and trim away all other shoots. Leave the plant alone until the third year.
Choose the two strongest offshoots from the central cane. Tie these offshoots to the trellis so they are parallel with the ground and the grape vine looks like a T. Prune away all competing offshoots by clipping them off directly at the main vine.
If your grape vine has grown tall enough to reach the second wire, perform this process again so the vine has four shoots tied to two parallel lines of the trellis. Again cut the top of the vine so it does not extend beyond the second arm of the trellis. Leave your plant alone until the next season.
Trim away offshoots from your vines. Remove all but one to two offshoots from the vines you've tied to the trellis, and keep offshoots that are close to the central trunk rather than far out on the vine.
Cut back your long vines, leaving no more than 10 buds per vine.
Prune off any growth that originates from the grape vine stem.
Repeat steps 5 through 7 annually. After four years, your grape vine is trained to its shape and won't need more training.