Pruning decisions are perennial choices made by every vineyard manager across the globe. With a few years behind it now, Kerry’s Vineyard (www.kerrysvineyard.com) is graduating from vinifera adolescence and transitioning into adulthood. As the vineyard solidifies into a relatively permanent yearly routine, a very important decision needs to be made regarding the training system of the vine.
The inherent nature of a vine and its chaotic growth patterns allows it to be sculpted into an infinite variety of somatic plant structures. There is no one right way to train a vine, but through cultural influence, local trends, experimental research and historical practices, certain standards of training have emerged. In Napa Valley, there are three main styles of pruning in the vineyard: head-trained, cordon, and cane pruning.
Head-training
Cane
Cordon
This year, in Kerry’s Vineyard, it is time to decide between either cordon or cane pruned training (if we wanted to go head trained, that decision must be made almost immediately after planting the vineyard, whereas the first few years of cordon or cane pruning are the same).
To put it simply, the arms of the vine that run parallel to the ground eventually produce many new shoots which will be the source of the individual grape clusters. In cordon training, the parallel arms are permanent structures on the vine and remain year after year whereas in cane pruning, the parallel arms are formed every year by leaving one-year old shoots leftover from the previous harvest.The main difference between the two styles is that cane pruning will yield slightly more fruit.
Because Cabernet Sauvignon is a lower yield variety and because Kerry’s Vineyard is on a hillside (as opposed to the valley floor), we have chosen to go with cane pruning for the Estate vineyard. As you drive up and down Hwy 29 and Silverado Trail in Napa Valley, you will see mostly cordon trained vineyards. Because these vineyards are planted on the valley floor, which is rich in nutrients and water, the vineyard managers are hoping to lower the yields of these vines by using the cordon training method. This will in turn help to balance the vine and produce better quality grapes. However, on a hillside vineyard, nutrients can be limited and water tends to drain very quickly, both factors that lead to lower yields on the vine. To compensate, the technique of cane pruning is utilized. Another benefit to cane pruning is it less harsh on the vine itself. With cordon pruning, each new shoot (usually 8 to a side for a total of 16) are pruned every year leaving the vine with many pruning scars. This leaves the vine much more susceptible to infections (such as Eutypa, described earlier). Because of this, excessive pruning can lessen the lifespan and efficiency of an individual vine.
So, as you can see, many key decisions are made when planting a vineyard and lots of work goes into maintaining a vineyard as well…..and we have barely even scratched the surface of the complexities that go into creating and maintaining a vineyard that will produce quality fruit year after year. It’s a good thing that we enjoy it so much!
Jason