The Oregon wine grape industry has established itself in the international market by producing premium wine. Excellence in wine grape production begins in the vineyard. Care in training grape and managing vines during the growing season results in quality fruit arriving at the winery. Canopy management is paramount in managing a vineyard sustainably. Proper canopy management can enhance fruit quality by providing the proper exposure of the fruit to light and air.
There different training systems and trellis designs used throughout Oregon's wine grape growing regions based on vineyard locations and needs. However, one of the more popular training systems used is the unilater or bilateral guyot, often referred to as VSP - Vertical Shoot Positioned. While VSP is actually just a management practice and not actually a training system, it is used as a synonym for the guyot system.
In Oregon's Willamette Valley, the VSP is cane pruned during the dormant season. To cane prune, the now 2-year old cane from last year and most of the one-year old wood (shoots) are cut off with the exception of 1-4 canes. One or two of the remaining canes are wrapped around the fruiting zone trellis wire and tied to form the cane for the new grwoth. Any remaining canes that are not affixed to the wire will be cut back to 1-2 buds and will serve as "renewal spurs" to provide for canes at pruning next year. Some vineyards use spur pruning instead of cane pruning. Spur pruning of a VSP vine requires that a semi-permanent arm, or cordon, be trained. From this cordon, spurs will originate and serve to provide the renewal zone. One-year old wood originating from spurs are pruned back to 1-3 buds, depending on your vineyard needs. All remaining one-year-old wood is removed. Spur pruning is a faster method of pruning and can be more readily mechanized than cane pruning. The majority of grape production in Oregon outside of the Willamette Valley utilize cordon-trained, spur pruned vineyards.
Bud break occurs after the dormant season pruning. Depending on the latitude, elevation, and variety of grape the compound bud breaks with the primary bud emerging first. In colder sites where the danger of frost occurs, the primary bud may be 'burned back' and the secondary shoot emerges. The secondary shoot contains less fruit and ripens later. In colder sites the secondary bud can burn back and final shoot or tertiary shoot emerges. In general the tertiary shoot has no fruit. Details of this will be offered in future OSU Viticulture Extension educational materials.
In the spring after bud break, the primary and often the secondary shoots emerge from the bud. The secondary shoot is removed when it is succulent to prevent crowding which can lead to disease and poor fruit quality. This very important step will also be covered in future instructional materials.
After the secondary shoots alone are removed the primary shoots are trained throughout the season in a process called 'canopy management'. During canopy management, the current season's growth is trained to optimize light exposure to the leaves and fruit.
The following are three critical steps involved in Canopy Management Videos: suckering, moving catchwires, and head thinning.
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Head Thinning: Before & After | ||
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Credits: | ||
Seasonal Information Bytes
The following are lecture audio and lecture slides from viticulture courses taught by Dr. Patty Skinkis, OSU Viticulturist in the V&E Program. Selections have been made to meet the needs of seasonal interest.
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