How to Prune a Multiple Trunk Grape Vine

Provide a trellis support system for your vine. Grapes require a trellis support to keep heavy foliage and fruit from rotting on the ground. Prune back all dead wood in the fall, once the leaves have fallen from the vines. Assess your vines, choosing the largest and strongest two or three vertical branches to serve as trunks. Train each trunk up a trellis support, preferably to the first horizontal support.

Train two branches, one on each side of each trunk, to extend horizontally along the horizontal portion of the trellis if such branches exist. If your vine is more than a few years old, train two additional branches to extend horizontally at each horizontal portion of your trellis. In the fall, prune all of the major horizontal branches back to no more than eight buds.

Cut all other branches off your vine in the fall. Cut all new shoots growing from the roots of your vines. Your vines should look extremely spartan after trimming, with only the two or three trunks and two horizontal branches extending from each trunk at each of the horizontal portions of the trellis. It is difficult to prune grapes too vigorously -- they will almost always respond by growing back with great vigor in the spring.

Cut your vines off at ground level in the fall if you wish multiple trunks but do not have multiple trunks. In the spring, your vine will produce multiple shoots. Choose the strongest two or three as your trunks and train and prune as previously described.