Cutting away the old, making room for the new
Derrick spur pruning cold hardy hybrid vines.
Did you know that grape vines only produce fruit on 1-year-old wood? It might sound like a lot, but every year we remove 80 - 90% of the previous year's growth to make room for the coming vintage!
Once the vines are dormant, we can start winter pruning. We prune to manage the yield, to maintain vine structure, and to remove any damaged or diseased wood. Pruning seems like it would be pretty straightforward, but it can make or break a season. It impacts the quality and health of the year's crop and can be the difference between making a profit or loss come harvest. And it's pretty cathartic to cut the previous season away and start fresh - for the vines, and for us too!
We use two primary pruning strategies: spur pruning and cane pruning. A little bit of vocabulary before we jump into explanations.
Cane: 1-year old wood
Cordon: 2+ old wood established as a permanent “arm” of the vine
Spur: a cane cut down to 1-3 buds
Spur pruning retains “old wood” cordons as permanent arms of the vine and cuts down the previous year’s canes to 1 – 3 buds. These buds will push new canes during the growing season that will carry that year’s fruit. If you have seen photos of gnarly thick old vines, they are most likely spur pruned.
Cane pruning on the other hand, does not establish a permanent cordon. Instead, every year, a new cane or two are laid in. This requires cutting out the majority of the previous year’s growth and can be pretty intimidating but can also reduce the risk of frost damage.
We are also firm believers that there is no "one size fits all" vineyard management plan and each grape variety and vineyard require a plan tailored to their location, microclimate, cold hardiness, and health of the vines. While we’re able to prune mature cold hardy hybrids starting in December, we hold off until March or April for:
Dev loves helping with winter pruning.
young vines
less cold hardy varieties (primarily vinifera like Riesling)
vineyard sites that have sustained frost damage in the past
"early pushing" varieties that will push shoots and leaves early in the spring and could be at risk of frost damage
The timing of pruning is really important because it has physiological effects on grapevines. Pruning can actually delay a vine from pushing shoots for 7 - 10 days. Different varieties will wake up at different times in the spring. For those earlier pushing varieties, even some of our cold tolerant hybrids, waiting to prune until later in the season can help them avoid frost.
Farming in northern Michigan is precarious and 2021 was a perfect example. We had a pretty hard frost on May 28/29 that did some serious damage here in the Tip of the Mitt. Helping the vines stay dormant as late into the Spring as possible is one way of helping them start the season on the right foot.
Before we started working in viticulture we assumed that vineyard work was seasonal. You see green stuff out there, you can work on it... nope! Vineyard work goes on year-round whether it's prep, planning, maintenance or managing the canopy and fruit during the growing season.
For more reading:
Illustrated Grape Vine Training Methods by Wine Folly
How to Prune Grape Vines – Cane and Spur Pruning Explained by Deep Green Permaculture
