Editor’s note: We’ve provided viticultural perspectives specific to both Spain and Portugal after Raymond’s article from renowned Spanish wine author, John Radford; Portuguese winemaker, Rui Reguinga; and Port winemaker, Oscar Quevedo.
For many of us, this is a particularly cold winter and not one during which we would consider venturing outside for very long unless absolutely necessary. For the winery team however, there’s another important event on the annual calendar, called pruning, and it’s an outdoors all-day task not for those averse to the cold.
After the harvest, and during Autumn, the vine’s leaves change colour and fall gently to the ground, prompting the plant to enter a dormant state. This state lasts well beyond other deciduous plants, awaiting that important moment when the average air temperature climb to more amiable conditions. Pruning involves the removal of much of that year’s growth and is typically carried out during winter and early spring. It’s obviously easier, and faster, to prune once there are no leaves on the plant, and the growth cycle has come to a halt; and although the timing varies according to many factors, pruning must be completed well in advance of the spring budbreak.
The principal aims are to prompt the vine to produce fewer, but larger bunches, of grapes and to control vigorous vine growth by limiting the vines ability to produce foliage. Another reason to prune is to maintain the shape of a vine or establish a young vine’s growth pattern in order to conform to the vineyard management practices. This control enables the vineyard team to train and manage rows of vines, often facilitating vineyard treatment regimens and harvesting plans. The types of training and methods of pruning employed are still regulated by the ‘Appellation Controlée’ structure in France and are often prescribed in the wine regulations of other old-world wine regions. These same controls are not usual in new world producers, but for many EU wine regions, the methods of pruning and training have been tried and established over many years and form a part of the region’s unique identity.
Essentially there are two differing methods of pruning employed in vineyards: Spur pruning or Cane pruning. They are the basis for a manifold range of more elaborate variations of these techniques.
Spurs are very short vine canes formed by cutting back the cane to less than four nodes – the part where the leaf is attached. The two fruiting canes that originated from this year’s growth are cut back: one being completely removed, the other to just two nodes and will later develop into two new fruit bearing canes.
It’s quite a severe form of pruning and it’s normal to remove almost all of that year’s growth, often leaving the vine looking rather debilitated. But once the growing cycle begins afresh, with the coming of spring, the plant flourishes again. The method and degree of pruning will impact the growth of buds in Spring and ultimately the quantity and size of the bunches and berries production.
Spur pruning is commonly used on free-standing vines such as those trained in the Gobelet style (as seen in photo) – common throughout much of Southern France. The vine trunks are maintained very short so that there is little more than Â½ metre of the vine above ground level, it resembles miniature aged wooden shrubs after pruning and looks rather bush-like during the growing cycle, giving rise to the term ‘bush vines’. Surveying the high-density plantings of sites in parts of Burgundy after pruning can make for an eerie landscape view, as a sea of tiny gnarled stumps across the expansive gently undulating vineyards stretches out before you.
The other common form of spur pruning is the Cordon. The vines typically have a similarly short trunk above ground level but a branch or cane is trained by wire along one side of the vine and this hardened wood and is never cut away, instead the spurs that it supports are pruned each year. This form of pruning is one of the most suitable for vineyards where mechanical harvesting is used and there are two forms: Cordon de Royat where a single cane is maintained and the double or bilateral Cordon where two canes are trained.
Cane pruning involves maintaining a cane and a spur. As part of winter pruning the previous years cane is clipped off and a new one from the spur is trained down to support that years growth. The quantity of buds that are left on the cane are determined by the regional wine regulations to encourage. Those regions of the wine world where these type of regulation don’t apply often have canes with many more buds producing more bunches, though planting densities are typically much lower. The Guyot system developed in France is a simple form of cane pruning and is practiced in single form or in double guyot form through much of Bordeaux. Vines are pruned to retain two canes with two spurs each, the canes are the trained in opposite direction with wires.
Pruning and vine training are closely related and the pruning method adopted will depend on the way the vine is trained. Training usually connotes the use of a supporting structure that can be anything from a stake in the earth to complex trellising systems.
The vine can be trained to greater heights depending on macro and micro-climatic requirements and historical practices. In the case of the long used Pergola training systems of the Vino Verde region of Northern Portugal the vines were trained high above the ground often allowing the producer to grow a second crop on the ground beneath. The method was believed to facilitate air circulation that mitigated the effects of humidity and damp in this marginal climate, though in recent years many viticulturalist are moving away from the Pergolas.
Vertical Shoot Positioning (VSP) is a training system achieved by tethering canes to trellis wires supported by posts down the rows and is used in conjunction with single or double guyot cane pruning or with cordon spur pruned vines. It can be spur or cane pruned and is widely practised in Bordeaux, Burgundy and Champagne.
One great way to get a better handle on training and trellising systems in particular would be to visit the very well presented demonstration at ‘Clos du Val‘ in the Stags Leap District in Napa, California where they maintain a mini-vineyard of 20 rows of Merlot each one trained and pruned to show a specific style including Scott Henry and Smart Dyson.
The reasons for adopting one method of training and pruning involve important factors such as climate, rainfall and sun exposure. Vine training is important in regulation the circulation flow of air within the vine canopy. Also, site, soil type and the variety of the vine will play a role as will economic drivers, mechanization or harvesting requirements and prospective yield. As mentioned earlier wine laws within EU wine producing regions will also specifically ascribe a training and pruning method right down to the number of buds permitted on a cane.
The time it takes to prune a vineyard depend on vine density – the quantity of vines planted – and on the pruning method employed. Increasing labour costs have led to the development of some mechanized pruning or pre-pruning systems but these are mainly for use in large scale vineyard operations and where the terrain permits.
For most quality producers across the manually tended vineyards of Europe pruning means wrapping up warm and spending days or weeks among the vines, armed only with a pair of gloves and some stout secateurs. The Wine Doctor also has a great article on pruning if you need more information.
John Radford (Spain)
I don’t think that, given modern viticultural techniques, there is a lot of difference between Spain and the rest of Europe. The high-profile regions (e.g. Priorat) tend to be making wines from ancient, low-yielding vines whch are likely to be pruned en vaso or, in hotter regions, en cabeza, although I was in Rías Baixas a couple of years ago and visited tiny vineyards with 300-year-old vines trained on pergolas, which is, of course, traditional in that area. Training on wires is a more modern technique, which is good for high-producing vineyards as in Rioja and Ribera del Duero, for example. I don’t think that Spanish viticulture is unique in any of this. Portugal, Italy and Greece and, indeed, anywhere else in the Mediterranean, have been using these old-fashioned systems for centuries in ancient vineyards. Most modern vineyards use more modern methods, but many of Europe’s most interesting wines come from traditional vineyards. (www.johnradford.com)
Rui Reguinga (Portugal)
In a short paragraph about pruning the vines in the South of Portugal, Alentejo, Ribatejo and Terras do Sado:
” The vines in the south of Portugal need to be pruned so that they may effectively resist the harsh climate. In the summertime, they are submitted to very hot temperatures and very little water. Thus, we use a traditional trellising system, similar to the south of Spain, which is in a “gobeletâ€ formation. In Portuguese, we call it ” taçaâ€ , which is typically used for old vines. But now with modern viticulture, we need to optimize the costs of production, and with mechanization, all the new vines have ” double cordonâ€. Now we prune, and the best way to do it in these poor soils, and limited climate conditions, is to have the vines pruned quite short.â€ (www.ruireguinga.com)
Oscar Quevedo (Portugal)
Pruning represents the basis for a good harvest. Due to the extreme weather conditions in the Douro, with very hot and dry summers, we do not want our vines to produce many grapes. We only leave 4 brunches per vine, with two buds each. This way the vines can better handle the ripening process and can live longer. For making good wines, we need good grapes, and the quality of the grapes is highly correlated with pruning philosophy. If you do not push the vines to hard, they will give you a good wine! – Oscar Quevedo (www.quevedoportwines.com)