Wine Arcana

Concept

Pruning and training systems

Also known as Vine pruning, Vine training

Pruning determines which parts of a grapevine remain to grow the next crop. Training arranges those parts in space. Together they establish the framework for canopy management: where shoots emerge, how much room leaves have, where bunches hang, and how workers or machines reach them.

A trellis is the supporting hardware—posts, wires, anchors, and stakes. Different vine shapes can occupy similar trellises. Looking at the wires alone will therefore tell you less than looking at the wood attached to them.

Read the wood before naming the system

A green shoot becomes a woody cane as it matures. During dormancy, that one-year-old cane carries buds from which the next season's shoots can grow. Those new shoots bear the bunches. Older trunks and arms support this annual renewal and connect it to the roots.

A spur is a cane cut back to a short section with a few buds. A cordon is an older arm retained over successive years. This distinction explains why a spur-pruned vine still needs new fruiting wood annually: the cordon stays, while the short pieces growing from it are renewed.

In cane pruning, the grower selects longer one-year-old canes and removes much of the previous fruiting framework. Selected canes are tied into place; short renewal spurs can provide shoots from which future canes are chosen. In spur pruning, many short fruiting units are distributed along retained wood. Both methods leave buds that produce new shoots; they differ in where those buds are retained and how the framework is renewed.

Bud position and the next crop

Buds near the base of a cane are less fruitful in some varieties than buds farther along it. Such a vine may need longer canes to retain enough productive positions. Varietal behaviour, the previous summer's light exposure, and winter injury all influence what the grower finds at pruning.

Bud number also sets the starting point for crop load. Pruning very severely can leave too few growing points for a vigorous vine, encouraging strong growth from those remaining. Leaving numerous buds on a weak vine can create more shoots and fruit than it supports adequately. The useful number depends on vine size and condition; it cannot be read from the pruning system's name.

Arranging the canopy

Vertical shoot positioning, usually shortened to VSP, guides shoots upward between wires. It creates an accessible fruiting zone beneath a wall of leaves. VSP describes shoot arrangement: it can accompany cane pruning or spur pruning. A high-cordon system instead places the arms higher and allows shoots to hang down. Trailing varieties generally fit this arrangement more readily than strongly upright ones.

Vigorous vines may benefit from divided canopies. Geneva double curtain separates two hanging curtains sideways; Scott Henry separates upward- and downward-growing foliage vertically. The extra space can expose leaves that would otherwise crowd one another, but keeping the curtains separate requires suitable support and seasonal work.1. University of Minnesota Extension, “Training systems for cold-climate grapes,” sections on shoot direction and divided canopies.

Hardware makes these choices possible. The fruiting wire supports the crop and its bearing wood; catch wires guide the growing shoots. Posts and anchors must withstand their combined weight and wire tension. Row spacing, machine access, and the height at which people prune and pick are part of the design, alongside the vine's growth habit.

Establishment and renewal

Young vines first need roots and a usable trunk, followed by the arms or renewal positions required by the chosen system. Their progress depends on growth, so a weak vine may need another season to establish the structure that a stronger neighbour has already formed. Early cropping is adjusted to that capacity.

Cold climates make renewal especially important. Growers may retain multiple trunks or suitable replacement shoots so that damage to one part does not require rebuilding the entire vine. Cane pruning renews the horizontal fruiting wood each year, while injured permanent cordons may require a more substantial replacement. These are practical responses to winter hardiness, not guarantees against injury.

Choosing when to cut

Late pruning allows assessment of winter bud damage. Under some conditions, delaying the final cut also delays development of the buds that will be kept, which can help manage spring frost exposure. Labour and the risk of breaking swelling buds constrain how late a vineyard can finish.

Pruning also opens wounds through which wood-infecting fungi can enter. University of California guidance describes delayed pruning, staged pruning, and wound protection as preventive tools against trunk diseases under California conditions. Their timing follows local rainfall and infection risk; a calendar recommendation from one region should not become a universal pruning date.2. University of California IPM, “Eutypa dieback,” management section.

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