As any keen gardener would know pruning is an annual activity which some of us look forward to with glee. It is a time of chopping off limbs to make way for new growth and life. In the vineyard you might be surprised to hear pruning is not as straight forward as ‘do it this way’ in every plot, it takes a bit of finesse.
Pruning starts when the vines are dormant in winter time, after leaf fall; a time when the vines vascular system is officially turned off. Like any plant which requires pruning the vines have been working hard before winter storing minerals and carbohydrates into the vine for winter storage. This is why you don’t want to prune too early, if you do you run the risk of the vines not having enough nutrients stored up to last the winter. Subsequently, if you do go early, your crop post pruning can be badly affected.
Your location comes into the decision making process in many ways but the first is when to prune during the dormancy cycle. Unless you’re in a frost prone area you most likely will prune late in the dormancy season to ensure buds break at the right time of year, but for most vineyards such as Tahbilk mid-season is about the time to get into pruning.
Pruning with purpose is very important in the vineyard. It can be a laborious task which nowadays is often replaced with mechanical machinery – but not always.
The reasons for pruning vines are:
- There would be no surprises to tell you a grape vine is aptly named because of its ability to climb or trail. So this means if you left a grape vine to its own devices it would be a sprawly woody stemmed plant which spreads across the soil. In commercial grape production the vines are trained upright onto what’s known as a trellis. This helps with harvesting. Pruning helps to keep the vines form year after year to ensure a smooth harvest.
- Pruning is also an important task in maintaining the number and positions of shoots on a vine each year. This is important because the shoot is where the vine stems will grow out from. So you need enough vine shoot growth to provide enough leaf cover to ripen the fruit. Again the number of shoots you leave on the vine every year will completely depend on the vineyards location, which way it is facing and the varietal planted.
- In any given season a vine produces a maximum amount of fruit. The act of pruning helps to contain the vine so it can work to produce a healthy crop with consistency year on year.
- Pruning is also a very fine art in some regions, in particular vineyards which are experiencing disease risk. It can take years and years to master the art of pruning for this purpose. This is particularly challenging in wet areas where the exposed freshly pruned vines have open wounds attracting fungal diseases.
A great example of both the benefits of pruning and the systemic challenges in areas experiencing disease risk is in the Barossa, South Australia. Here they are experiencing a problem called ‘Dead-Arm’, a grape canker which gets into the vine at pruning time and causes deep wood rot in the trunk of the grape vine. It takes a few years for this disease to progress and then eventually the whole vine dies. Here pruning is really critical as the open wound at the wrong time of year can allow the disease to enter and once it is there it is there.
So now you know.
Pruning with purpose is one step in the many critical parts of ensuring we get high quality grapes to bring into the winemaking process. A task every keen wine drinker should experience now and then. After getting into the vineyard and having a go at pruning you will grow an appreciation of the art involved. It’s just not as simple as we think!