© Quinta de la rosa 2013
"Correct pruning of dormant vines is one of our most important vineyard tasks."
The pruning of the dormant vines is one of the most important and expensive vineyard operations that we carry out at La Rosa. Careful pruning allows us to regulate the amount of crop produced by the vines and helps us achieve a "balance" between shoot growth and fruit production.
Pruning the vines at La Rosa occurs in mid-winter when the vines are dormant. The pruning involves removing last year's growth and leaving behind the number of buds that will determine the number of shoots and to an extent the production for next year. When too many buds are left, the individual shoots will be weaker which can lead to over-cropping, poor fruit quality and a weakening of the vine. While if too few buds are left the shoots will be overly-vigorous, dense shaded canopies will develop and fruit quality will again be affected.
The skilled pruner assesses each vine individually taking into account the vine's vigour which is partly determined by the previous season as well as the vineyard site and the fertility of the soil. In general, we leave fewer buds on less vigorous vines and a greater number of buds on the more robust vines.
There are essentially two types of pruning, cane pruning and spur pruning, both of which are used at La Rosa.
The majority of our vines at La Rosa are spur pruned. The vines are unilaterally trained to produce a permanent cordon from which the shoots grow vertically upwards into the VSP trellis. During the dormant season the canes (dormant shoots) are spur pruned to either one or two buds depending on the vigour of the vine. On average we leave approximately eight buds per vine.
During the training of the vine, we make sure that the spurs are evenly spaced along the cordon to prevent overcrowding of the shoots. Manual hand shears are used to prune and every cut is angled away from the bud, at approximately a 45 degree angle, to ensure the natural and healthy growth of the bud.
We have found that spur pruning is an easier type of pruning to teach to our workforce, it is less labour intensive and therefore more economical. Importantly, the fertility rates of the basal buds are sufficient so the vines produce a balanced production each year. In addition, spur pruning the vines gives a good orientation of the vegetation creating a uniform canopy suited to our VSP trellis system.
Cane Pruning or The Guyot System
Traditionally, all the vineyards in the Douro Valley were cane pruned but now only a few of our older vines are pruned in this way. With this system, the vine is trained to a head of two short arms and it is from here that shoots are produced and grow. In the dormant season, the canes are pruned away to leave a two node renewal spur and a cane. The cane determines the production for this year while the renewal spur will produce the wood for next year's cane. The fruiting cane is then trimmed to a length of three to five buds, the tendril and laterals are removed and finally the cane is tied down onto the fruiting wire. We leave either one or two canes depending on the vigour of the vine.
Cane pruning is a more skilled type of pruning than spur pruning as you have to identify the desirable fruiting canes for next year. The fruiting cane should have firm wood, healthy fruitful buds and be round in cross section. The pruner also needs to ensure that the fruiting cane and renewal spur are well positioned close to the trunk of the vine.
Cane pruning is more labour intensive and costly than spur pruning as an extra vineyard pass has to be made to tie down the fruiting canes. It is particularly suitable for grape varieties that are not very fruitful in their basal buds.