An Education on the importance of Winter Pruning
While you and I are dashing around getting ready for Christmas, vineyard owners in the northern hemisphere are out in their vineyards starting to carry out the all-important winter pruning of their vines. Of course, in the southern hemisphere this will occur during their winter around June/July.
Vines will happily grow and produce grapes without any pruning whatsoever, lots of grapes in fact, so it begs the question, ‘why on earth should viticulturalists bother pruning at all?’
Here are a couple of key reasons for carrying out a good winter pruning regime:
1. Improving Grape Quality
It’s in every winegrower’s interest to produce the best quality fruit possible as this will translate directly into the wine for that season or vintage. The best way to achieve this is by limiting the amount of fruit and foliage that each vine produces so that all the vine’s resources and energy are channelled into fewer grapes.
Of course, producers of lower-quality table wines are more motivated by quantity and less by quality so will probably pay far less attention to this!
As the seasonal temperatures drop and the vines go into ‘sleep mode’, it’s time to get out the secateurs (whether mechanical or manual) and trim away the current year’s growth, making sure either one or two potential canes or spurs with buds are left for the next vintage. Further removal of selected buds will also limit how much growth the vine will produce when the temperatures start to rise again.
Basically, the principles for winter pruning are much the same for grape vines as for any perennial flowering or fruiting shrub. And as vines are particularly vigorous, like some climbing rose species, they’ll generally benefit more by being cut back harder.
2. Improving Grape Health
Modern wisdom says that in order to grow your vines optimally, you need to consider two key factors; climate and soil. On a very elementary level, a vine needs moisture, warmth, sunlight and nutrients in order to grow healthily, all of which are obtained from climate and soil. But too much of any of these elements can be detrimental to the vine so the key is striking the right balance.
There are further considerations that a grower needs to take account of when trying to decide how the vines are to be managed. Grape variety, age of vines and vigour of the vine’s growth all play an important part.
Once you’ve established all these elements, you can determine how the vine should be trained. For example, in a cooler more marginal climate like Champagne, Pinot vines tend to be trained with the trunk bent over horizontally and tied to a wire with a number of spurs that are positioned vertically and fixed to one or two higher wires as they grow. This system, known as Cordon de Royat, allows for greater exposure of the grape bunches to sunlight for ripening and to aid air flow to keep diseases minimised. In a hotter climate like the Mediterranean, you’re more likely to find vines growing ‘wild’ like bushes (known as Gobelet in France) where the plentiful foliage helps to shield the bunches from the harsh summer sun.
What are the Classic Pruning Methods?
So we’ve already touched on a couple but here’s a summary of the most common pruning systems found around the wine world:
Single Cordon Spur-Pruned (Cordon de Royat)
A spur-pruned system that’s not only associated with cooler zones like Champagne but also warmer climates like southern France, Tuscany and large areas of Spain too. As there’s just one cordon tied down (as in the main trunk and not a replaceable cane), growers have the option of pruning mechanically which is considerably faster than by hand.
Double Cordon Spur-Pruned (Cordon Double)
As previous but the trunk is split into two cordons that form a T-shape. This works well in regions prone to drought conditions as there are far fewer plants per acre, and since there is a much lower planting density, the initial set-up costs are considerably less too.
Head-Trained/Bush Vine (Gobelet)
The vine is trained close to the ground in a free-standing bush with three to five branches each yielding one or two spurs. These are commonly found in hotter regions like Mediterranean countries and parts of Australia or conversely where they’re exposed to extreme cold conditions like wind-ravaged high-altitude vineyards, especially in northern Spain.
Single Guyot (Guyot Simple)
One of the world’s most common training methods, particularly in cooler climates. Each trunk has a single fruiting cane, that’s attached horizontally to a wire, and one renewal spur which becomes the following year’s fruiting cane. There are additional wires to help support the canopy as the spurs shoot upwards. This method suits lower vigour vines and is relatively easy to maintain. It’s also the preferred method for winemaker’s working with smaller yields and more premium quality.
Double Guyot (Guyot Double)
As previous but effectively doubled with two fruiting canes and two renewal spurs. The chief benefit here is cost saving due to the considerably lower plant density, as with Double Cordon. This method is particularly popular in Bordeaux but is widely used throughout Europe as well as further afield.
So while you’re sitting in front of your computer putting together your WSW Christmas wine order, spare a thought for those hard-grafting vignerons out in all weathers prepping their vines for the next season’s bottled pleasures!