Vine pruning is one of the most important tasks of the year. It regulates the crop load of the next vintage.
But what do we mean by ‘load’?
The term refers to the maximum grape crop that can ripen without compromising wine quality. The amount is directly affected by the number of buds, measured per vine or surface area.
In winter, the buds remain dormant within the nodes. Come spring, they will develop into shoots and grape clusters. But the fruitfulness of the buds has already been determined last summer by the temperature and sunlight intensity at the time, and other factors that will influence the fertility of the bud.
The ideal pruning method to use now is the one that will keep the right number of buds on the vine so that grapes can grow and ripen in balance with the vegetative vigor of the vine.
Winter pruning is also a site-specific task. Thus, whilst being mindful of the conditions of the past year as well as the coming vintage, we need to decide on the right method that suits each one of our vineyards.
The main system we use is a spur-pruning method called the bilateral cordon Royat. The vine trunk is left to spread two permanent ‘arms’ or cordons. Last year’s upright canes on each cordon are trimmed to six fruiting spurs with two buds each.
Some vineyards that are either less fertile or high yielding, which are mainly located in Amyndeon, are cane-pruned according to the single or double Guyot method, which requires the cordons to be renewed every year.
We experiment as well with other training techniques such as the Lyre and Cazenave systems so as to evaluate their effect on the yield and oenological quality potential of the grapes.
It is imperative to maintain the plant health of the vine trunks by disinfecting shears and pruning cuts because wood diseases are always lurking. In susceptible varieties, we only start pruning after the vines have started to weep since this acts as a natural barrier against infection. Examples of such diseases are Esca and Eutypiose. They can cause gradual or immediate dieback of the vine’s arms or trunk.
The timing of pruning, too, impacts the development of the buds: the earlier pruning is carried out, the earlier budding occurs. Since this can cause damage in the event of spring frost, early-growing varieties such as Chardonnay and Traminer are pruned as late as possible.