In episode 37 of the Vineyard Underground podcast, we had a conversation about unique or alternative pruning scenarios and methods with guests John Thull and Marco Tessari. We discussed viticulture for cold climates, unique pruning techniques from around the globe, and more. John has a degree in biology with a plant focus and spent time in Germany doing an apprenticeship. He now lives in Minnesota, where the temperatures can get well below freezing, and specializes in grape breeding and enology, with a focus on cold-climate grapes and wine. Marco is from Italy and came on for his second time to teach us about two unusual pruning techniques: the Sylvoz and Cazenave methods.
Read on to learn John’s strategy for pruning in cold weather climates and about the Sylvoz and Cazenave pruning techniques.
John’s Strategy for Pruning in Cold Weather Climates
Growing grapes in cold climates like Minnesota, the Midwest, and the Northeast can be challenging due to shorter frost-free days and heat accumulation during the season, along with the extreme cold temperatures that can reach 30 below. Keeping this in mind, it’s important to prune the vines strategically and not so tightly that there’s no room for “insurance buds” or backups. Pruning vines too tightly in cold climates can lead to a lot of blind nodes and buds not pushing, resulting in a lower yield of shoots growing the following season. Therefore, it’s important to always prune in a way that leaves backups to the backup to the backup – with some insurance buds left in place!
Getting Bud Numbers Up Without Causing an Imbalance On the Vine
To increase bud numbers without causing an imbalance on the vine, grape growers like John employ a technique known as “spare parts pruning” or “dirty pruning.” This involves intentionally leaving a few more buds than usual to ensure better bud survival during the cold season and early spring. Once the growing season begins, these extra buds can be thinned out. Specific grape varieties that survive well through the harsh winters, according to John, are Frontenac, Frontenac Gris, and Frontenac Blanc.
Unique Pruning Techniques From Around the Globe with Marco
Both the Sylvoz and the Cazenave methods are based on the cordon, spur pruned vine structure, which is the most common way of training vines in America. The Sylvoz technique involves using canes that grow quickly from the top to the bottom, allowing the vine to add a significant number of buds. With this technique, the vine can have one, two, or three canes with around eight buds each, while the traditional method would have only about five spur positions with ten buds in total. This approach is utilized for many varieties of grapes, including Prosecco, Glera, Cabernet, Merlot, and Chardonnay.
The Cazenave technique is similar to the Sylvoz, with the difference being that the cane arches down like an umbrella, which results in more buds per spur position. For this method, the cane should be derived from the top position of the spur, encouraging the spur position below to act as a renewal spur, producing shoots to create a shoot for the future spur underneath and a shoot for the longer fruiting cane the following season. These unique pruning techniques offer grape growers options to experiment with and can potentially lead to better yields while maintaining good quality.
If you want to learn more about alternative pruning methods, check out https://www.vineyardundergroundpodcast.com/vu037.