Pruning Grapes, Two Common Methods

By John Martin

A single well-trained vine growing along about 12 feet of trellis or fence line can produce tens of pounds of fruit for the table or about a gallon of wine. However, to maintain good yields, grapes need yearly pruning to a controlled shape that allows light to reach the developing fruit on well-spaced vines. Without yearly pruning, you’ll soon have a wildly vegetative thicket bearing little or no fruit.

The two most common methods for pruning grapes are “spur pruning” and “cane pruning.” The latter is generally best suited to table grapes and some wine varieties with American heritage. 

The difference between spur and cane pruning lies in the permanent structure of the grapevine. A spur-pruned grapevine has the shape of the letter T with a vertical trunk and two horizontal arms called cordons. These “old wood” cordons grow permanently along support wires. 

Each cordon retains 15-40 buds spaced six-inches apart along its length in the spring. During the growing season, each bud sends out a long fruiting cane that develops one or two grape clusters and many leaves. Sometime in the dormant season, the spur-pruner cuts every first-year cane near the cordon, leaving a single bud on each remaining stub of cane, called a “spur,” that will send out the next year’s fruiting cane. 

A cane-pruned vine looks much like a spur-pruned vine at the end of a growing season, but instead of the many cuts to vertical growth made when spur pruning, you arrive at the same shape with two severe horizontal cuts. Think of cane pruning as constant renewal of cordons. The permanent structure of a cane-pruned vine is just its trunk. The arms of the T never grow to old wood cordons in the cane pruning system.

Instead, in the dormant season, select two strong fruiting canes emerging near the top of the trunk for use as new horizontal arms. Make two drastic cuts to last year’s horizontal arms to remove all the other new growth. Then, lift and tie the two uncut canes horizontally onto the support wires. These two canes have buds at every leaf node from last season. Next year’s fruiting canes will emerge from these buds.

If the vine is American or a hybrid with American ancestry, vines can be extremely long, so you’ll probably need to shorten the newly tied horizontal canes to fit your space.