Ed Hellman, Texas AgriLife Extension
The first step in pruning is to identify the fruiting canes for next year. Desirable fruiting canes develop under conditions of good sunlight exposure, which is a function of the training system, last season’s pruning level, and canopy management practices. Good sunlight exposure promotes bud fertility and wood maturity. Select fruiting canes and renewal spurs from positions close to the trunk head to prevent the arms from becoming too long, which will cause a nonproductive gap in the canopy above the head. The characteristics of desirable fruiting canes are:
After selecting good fruiting canes (either one or two depending on the training system and vine spacing), select another good, well-positioned cane as a renewal spur and prune back to one or two buds. Periodically, you may want to retain a watersprout (during shoot thinning) closer to the trunk than the current renewal spur. At the next dormant pruning, the watersprout cane becomes the renewal spur. This practice keeps arm length from becoming excessively long. If the vineyard is double-trunked, leave a cane and a renewal spur on each trunk.
An alternate method does not retain a separate renewal spur. Instead, it is assumed that in the next dormant season, a good basal cane from last season’s fruiting cane can be selected as the new fruiting cane. Remove the remainder of last year's fruiting wood and all other extraneous canes, including suckers and watersprouts. Trace the suckers back to their source and cut them back completely to remove all basal buds. Trim the fruiting canes to a length that retains the desired number of dormant buds, then make the pruning cut through the next node (bud) beyond the retained buds, so the enlarged portion of the node prevents the tie from slipping off. Next, remove all tendrils and laterals, bend the cane up onto the fruiting wire, wind it around one time, and finally tie at the end.
If wood diseases are a high risk, all prunings should be removed from the vineyard and disposed of away from the vineyard.
Cane Pruning Grapevines video, Oregon State University
Structure of Spur and Cane Pruned Vines video, Oregon State University
Reviewed by Eric Stafne, Mississippi State University and Sara Spayd, North Carolina State University