Definition: Pruning (of vines)

A method of training vines using a technique that involves cutting the shoots. Wild vines produce numerous weak shoots with irregular, poor-quality fruit. By carrying out this essential pruning operation, it is possible to balance the production of vegetation and fruit, which are always in competition with each other. By limiting grape production, it is also possible to improve quality. Through winter pruning, the winegrower removes some of the shoots from the previous harvest, limiting the number of buds and, as a result, the future production of each vine, also known as the fruit load.

The type of pruning varies from region to region, depending on local traditions, climatic conditions and the configuration of the vineyards. It is pruning that gives each vineyard its own unique appearance.

Green pruning is carried out during the growing season: suckering takes place in the spring and involves cutting back suckers, i.e. unproductive shoots. Summer trimming involves removing excess foliage and green shoots. Trimming improves aeration and sunlight exposure for the bunches. Topping is a similar operation carried out in mid-June, after flowering, which involves cutting the ends of the shoots, as limiting their growth encourages the development of young bunches. Excessive vigour in the shoots causes nutrients to migrate to the tips, always to the detriment of the developing fruit, which, lacking nourishment, fails to develop and falls to the ground: a physiological imbalance known as coulure.

Pruning, the act of cutting, which selects the number of shoots and their position and limits their length, aims to regulate fruit production in terms of both quantity and quality. This operation slows down the ageing of the vine and prolongs its production and vigour. Pruning can in principle be carried out throughout the dormant period, but given the risk of frost, it is generally done between December and February.

There are different pruning systems:

Goblet pruning is typical of traditional Mediterranean vineyards. This type of pruning does not allow for mechanisation of the vineyard. The vine stock takes on the appearance of an inverted cone.

Guyot pruning is the most common method throughout the region. It has become very widespread because, when combined with trellising, it is suitable for mechanisation of the vineyard. The vine stock takes on the appearance of a short trunk with one or two arched shoots attached to a wire.

The Lenz-Moser system consists of long pruning on tall vines. Suitable for vines with low planting density, it allows for higher production per vine.

In Royat cordon pruning, the vine stock has a fairly long trunk and the arms are horizontal, aligned on a wire. This pruning system is useful for productive grape varieties. Well suited to machine harvesting, this pruning method produces well-spaced and airy bunches. There are many different vine training systems, depending on local customs. We have only listed the most common ones above.

The ratio between the harvest yield and the weight of the vine shoots after pruning is the best measure that can be used to assess the balance of the vine. The ratio between the harvest and the weight of the vine shoots is a good indication of the balance between fruit and vegetative growth. Very vigorous vineyards have low values and overproducing vineyards have very high values. This calculation must be made on ten or more vines. The weight of the vine shoots should be between 1/5 and 1/10 of the harvest, otherwise the vineyard suffers from an imbalance.

Pruning stories: Noah was the first winegrower, so he must have known how to prune.

An unmanaged vine produces wood and grapes as big as buckshot. In 2000 BC, the Egyptians pruned their vines.

In ancient times, a homo sapiens noticed that a vine branch grazed by wild goats produced beautiful grapes at eye level, instead of small clusters 10 metres above the ground.

The famous story of Saint Martin's donkey eating a vine and leading to the discovery of pruning in^{the 4th} century AD is nothing more than a tall tale. At most, he discovered trimming, or green pruning!