Vine Pruning With Our Vineyard Manager Dave Shein

It’s a cold and misty winter Napa Valley morning when we pull up at Soda Canyon Ranch, our Napa Valley estate vineyard in the southern benchlands of the Vaca Mountains. The fog is starting to lift over the hills and vineyard crews are already hard at work preparing a vineyard block for replanting. Although winter might seem like a quiet time in the vineyard, it’s actually one of our team’s busiest seasons. Much of the heavy lifting and preparation for the next growing season is done while the vines are dormant.

Soda Canyon Ranch is home to many of our Napa Valley Cabernet Sauvignon vines, along with blending varieties like Merlot and Petit Verdot. It’s the perfect location for our mission this morning – a crash course in pruning methods. Felcos in hand (the industry-standard pruning shears), we’re here to meet with Dave Shein, our Napa Valley vineyard manager, and learn the difference between two types of pruning methods: spur pruning, or what one might think of as the typical way of pruning a grapevine, and cane pruning, an updated take on a traditional method that we implement at certain Silver Oak and Twomey estate vineyards.

Dave Shein, vineyard manager

“Pruning is one of the most important things we do for wine quality. In large part, it sets the stage for the upcoming vintage.”
– Dave Shein, Napa Valley Vineyard Manager

The difference between cane and spur pruning
The differences between cane and spur pruning are illustrated in this infographic

With his natural and easy smile, Dave welcomes us to the Ranch and we start off down vineyard rows still wet with dew – hastening our gait to keep up with Dave’s large strides. Tall and broad-shouldered, Dave pretty much fits exactly what you might mentally picture as a vineyard manager. As we walk, Dave tells us that the vast majority of our acreage is currently spur pruned, but our first stop this morning is at one of our few blocks of cane pruned vines. We’ve found our experiments in cane pruning to improve management of vine vigor, which in turn improves wine quality. Over time, Dave expects cane pruning will become our standard. All of our new plantings – like the block we just saw being prepped for replanting and our new vineyard plantings in the Alexander Valley – will be cane pruned.

As you might expect being pruning newbies, we’re full of questions. Lucky for us, Dave is game for many a teachable moment.

What are the key differences between cane and spur pruning?

Spur-pruned vines have the look you might expect from grapevines. They are cordon-trained, meaning they have that classic “T” shape you see when driving by a dormant vineyard. All the wood that makes up the “T” is old wood that has been trained over many years into that shape. Those horizontal arms are called “cordons,” on which are spaced vertical spurs every six inches or so (approximately a hand-width). It is from those spurs that we get new vine growth each season.

Cane-pruned vines, on the other hand, are not trained in a “T” shape. They consist of a vine trunk and head, lacking cordons on either side. Instead, two canes – shoots from the previous year’s growth – are left during pruning and laid down on training wire. New growth comes from the nodes, or buds, on those canes. And at the end of the growing season, those one-year-old canes are completely removed and new, fresh canes grow in their place.

Why are we moving toward cane pruning?

One of the key benefits of cane pruning is that it gives us more flexibility in managing each individual vine. We can leave different length canes depending upon the strength of the vine, or even change the number of canes from year-to-year. Overall, we’ve found cane-pruned vines provide more consistent yields and production. After all, balanced vines produce the best wines.

In contrast, spur-pruned vines with cordons have fixed positions, leaving us less flexibility to prune based on vine vigor. Plus, if we lose a spur position in a given year, it can be difficult to regenerate. There are also lots of old wood pruning wounds on a spur-pruned vine, and sap has to flow around these wounds to feed new growth.

Does cane pruning require any additional training?

Absolutely. We call our cane pruning crew members our “brain surgeons” because each individual cane-pruned vine needs a skilled set of eyes to determine how to properly balance the vine for the coming growing season. We’re all actually going “back to school” to learn more about cane pruning with a 10-day intensive training this spring.

Our cane-pruned vines are trained in an arch along the trellis wire – we’ve never seen that before. Is there a reason?

It has to do with apical dominance. In layman’s terms, vines will have some buds that will always push more strongly than others, so by arching the canes we encourage the middle buds on the canes, which typically don’t push as strongly as the inner and outer buds, to produce more robust, fruit-setting shoots.

It looks like we’re the first ones in the vineyard this season to prune vines. When will our crews start the process?

Not long! Our crews were out in January to pre-prune. That’s when we cut all of last year’s shoots back to 5-6 buds. This gets rid of most of the vine’s growth, which helps our final pruning pass go more quickly. This allows us to do our final pruning pass later in the season, in late February to early March, when the weather is drier and vines are less likely to contract eutypa, a disease that spreads in wet weather through open vine wounds. An additional benefit of later pruning is delaying budbreak, which helps avoid frost on new growth.

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