Pruning is the intentional, annual removal of specific wood to manage a grapevine’s growth and direct its energy toward fruit production. This practice is fundamental because grapes develop only on shoots grown from buds on one-year-old wood. The primary goals are to maximize fruit quality and size, control vegetative vigor, and establish an open structure for optimal air and light exposure. This careful management ensures the vine maintains a sustainable balance between producing foliage and bearing fruit.
Preparing for the Cut: Timing and Equipment
The optimal time to prune grapevines is during the dormant season, typically from late winter to very early spring. This window is specifically before the buds begin to swell and before the sap starts to flow throughout the vine. Pruning too late, just before bud break, can cause the vine to “bleed” sap heavily from the cuts, which indicates a loss of stored energy.
Three main tools are needed for this task: sharp bypass hand pruners for cutting smaller, one-year-old canes, and long-handled loppers for removing thicker, two-year-old wood. A pruning saw may be necessary for older, heavier wood or neglected trunks. Sanitize all cutting tools with a disinfectant solution between vines to prevent the potential spread of fungal or bacterial diseases.
Structural Development: Pruning Young Vines
The first three years of a grapevine’s life focus entirely on establishing a permanent structure, not on maximizing fruit yield. In the planting year, the newly set vine should be cut back severely, leaving only two or three healthy buds above the soil line to encourage a strong root system. All shoots that emerge should be allowed to grow for the first season, or all but one strong shoot should be removed to focus growth on a single trunk.
During the second dormant season, select the strongest, straightest cane to become the permanent trunk, cutting it back to the height of the lowest wire on the trellis. All other canes are removed completely at the ground level. The selected trunk is tied securely to a stake or the wire.
Year three involves establishing the permanent horizontal arms, known as cordons, or defining the head structure, depending on the chosen training system. The goal is to select two canes growing near the top of the trunk and train them horizontally along the trellis wire. Prune these canes to a length appropriate for the trellis space, creating the permanent framework for future fruiting wood. By the fourth growing season, this established structure is ready to produce a substantial crop.
Annual Maintenance: Mastering Cane and Spur Pruning
Once a grapevine is mature (around its fourth year), annual dormant pruning manages the one-year-old wood that will bear the next season’s fruit. The two primary methods are spur pruning and cane pruning, and the choice depends largely on the grape variety being grown. Spur pruning is common for varieties like Vitis vinifera where the buds closest to the cane’s base are highly fruitful.
Spur Pruning
This method relies on a permanent cordon, or arm, extending horizontally from the trunk along the trellis wire. The previous season’s vertical shoots growing from the cordon are cut back to short spurs, typically leaving one to four buds per spur. These spurs should be spaced four to six inches apart along the cordon, and all other excess growth is removed.
Cane Pruning
Cane pruning, often called the Guyot system, is utilized for varieties like Concord or American hybrids that have less fruitful basal buds. This technique requires removing almost all of the previous year’s wood, avoiding the creation of permanent cordons. Instead, the pruner selects one to four of the most vigorous, pencil-thick, one-year-old canes and cuts them to a length of eight to fifteen buds each.
The selected fruiting canes are then tied down horizontally to the trellis wire to maximize fruit production. Additionally, a one- or two-bud renewal spur is left near the trunk’s head to ensure a supply of high-quality canes for the following year’s pruning cycle.
A rule of thumb for balancing the vine’s vigor is the “Balanced Pruning Method.” This method suggests retaining a specific number of buds based on the total weight of the removed wood. For example, a common formula is to retain twenty buds for the first pound of one-year-old prunings, and then ten additional buds for every subsequent pound, aiming for a total bud count between thirty and fifty per vine.
Immediate Post-Pruning Care
After making the necessary cuts, immediate attention to sanitation and securing the vine is required. All pruned wood and canes must be removed from the vineyard area and destroyed or disposed of. This debris can harbor overwintering fungal spores and disease pathogens, and eliminating this material reduces the overall inoculum load, protecting the newly cut wounds.
Following the removal of excess wood, selected fruiting canes or newly established cordons should be immediately tied securely to the trellis wires. This action guides the future growth pattern and prevents wind damage before the new season’s shoots emerge. Tying must be completed before the buds begin to swell, as developing buds are easily dislodged.
For small cuts made during the cold, dry, dormant period, the vine’s natural defenses are usually sufficient to close the wound. However, large cuts into older, multi-year wood (such as the trunk or a cordon) create vulnerable entry points for serious fungal pathogens that cause Grapevine Trunk Disease. To mitigate this risk, treat these larger wounds with a registered pruning wound sealant or a protective fungicide immediately after the cut is made.