The grapes are in, the weather has cooled down, and the leaves have fallen off the vines. At this point the vines are going into hibernation. The early winter rains however encourage the grasses, which are a juicy meal for the resident roos. Piero, our vineyard pouch keeps a wary eye on their whereabouts. The wines are now through fermentation so the work of the fermentation yeast is done for the year.
The main task during the winter in a vineyard is PRUNING.
- Pruning broadly controls how much fruit the plant produces, and where.
- Too much fruit takes a toll on the plant and results in uneven yields over the years, it can also result in uneven or late ripening, which can reduce quality in very cool years.
- Too little, and you cannot make enough wine per vine, so unless you can charge mega bucks, it will not be economic, since all the other costs will be the same.
- Fruit yield is especially important in cool climate vineyards because it strongly affects wine balance, the relative amounts of acid, alcohol, tannins and flavor.
- Fruit should be kept to a zone for ease of picking, and control of ripening, the shading or otherwise of the fruit and disease control.
There are a number of ways to prune a vine. Commercially, spur and cane pruning are widely used in cool climate vineyards.
Spur Pruning vs Cane Pruning
Spur pruning tends to be preferred in young vineyards but as they age cane pruning can improve declining yields, With cane pruning, 2-4 of the strongest canes on the head of the vine are chosen, and the rest of the canes removed. The chosen cane is tied down onto the wire, which is an extra step. For 10 canes that does not really matter for 1,000s it does!
At Greenhill Wines, we spur prune our 20-25 year old vines, the existing arms (cordons) along the trellis wire stay and spurs are left approximately a fist apart, from which the new canes will grow, 2 buds per spur is preferred.
The fruiting zone for both methods is the same, just above the crown or cordons, any canes growing underneath or on the trunk (water shoots) are removed.
When to prune?
Once the vine has become dormant, pruning can start. The accepted mantra is to prune before the sap starts flowing in the spring, and in frost prone vineyards pruning later delays bud burst which limits risk of frost damage in the spring. It does depend on the vineyard, and only working with a vineyard over several years can answer that question.
We prune mid July to early August – depending on the weather! It is not considered wise to prune while its wet since this can encourage ‘dead arm’ disease, a nasty fungal infection which can eventually kill the vine.
Vines that have lost their leaves have a wonderful sculptural quality
All these canes will be reduced to 2 spurs at each node, the nodes are about a fist apart
The aim is to have as few ‘staghorns’ like this as possible. The canes should come from as close to the cordon as can be managed, but with older vines- staghorns can develop.