This winter has been one the Treasure Valley will not quickly forget. It’s been decades since we’ve seen this kind of snowfall and low temperatures. So besides having to shovel our driveways on a daily basis and keep a healthy stock of snow-melt in the garage, we have also been thinking about how this cold spell will affect Idaho’s 2017 grape production.
When a vine is hit by a cold snap, what really suffers are its dormant buds, which are what develop into fruit in the spring. The buds that develop into fruit are bundled up together inside an external, scaly, protective layer.
BUDS ARE REALLY IMPORTANT
There are three types of buds: primary, secondary, and tertiary. Two of these buds can produce fruit, but most of the fruit comes from the primary bud. Unfortunately, the primary bud is most vulnerable to the elements and gets damaged first by the cold. In a typical Idaho year the primary buds emerge from winter unscathed, so we don’t have fruit develop from the secondary buds. But if the primary bud is unable to produce fruit, the secondary bud can step up to the plate to produce back-up fruit.
If both the primary and secondary buds are damaged, the tertiary bud (which is most protected) will bloom. The tertiary bud’s evolutionary purpose is to propagate the plant and keep it alive, so we don’t get any fruit from it. But sometimes the cold damage is so bad that the tertiary bud gets damaged, in which case the entire portion of the plant above ground (the scion) can collapse.
GETTING TO THE ROOT OF IT
In most wine regions, a tertiary bud-killing winter would mean that grape growers would have to completely replant. This is because most vines are grafted onto rootstock. Rootstock became somewhat of an industry standard after the Great French Wine Blight in the mid-1800s, when a grape-terrorizing aphid, phylloxera, all but wiped out vineyards throughout Europe. While rootstock is incredibly resilient against insect infestation and disease, a nasty winter freeze will kill the whole plant because its graft point is directly exposed to the elements.
Fortunately, Idaho isn’t like most places. Instead of using rootstock, most of our vineyards are own-rooted vines. For Idaho vineyards, the worst case scenario after a freeze would be that our growers would have to cut the plant back to its own-rooted vine roots, which stay insulated by the soil and the excessive snow and are not compromised no matter how malicious the cold weather decides to be. From there, a new scion can be trained in the vineyard. This leaves us about 1-2 years behind in production and a few years down in tonnage, but it’s a lot better than having to totally replant- a 5 to 8 year process.
WHAT ABOUT IDAHO'S VINEYARDS?
We won’t know for certain what to expect until each vineyard assesses its own plants because damage can vary even row to row. However, the forecast isn’t looking good. The Idaho Wine Commission has hired a Viticulture Specialist to work with our awesome grape growers. His job is to help us cultivate even better vineyards by sharing his knowledge and experience on canopy management, irrigation, and other grape growing best practices.
Unfortunately, his assessment concluded that the winter hit us pretty hard. There may be more damage than we were hoping for, and almost all of our vineyards will likely see some degree of weather damage. That means that some vineyards may need to cut their vines and re-train them this season. Again, not ideal for a 2017 vintage but all is not lost, the vines will come back next year.
While we were hoping the winter would have been a little easier on our State’s vineyards, Mother Nature doesn’t always consult us prior to determining the weather. 2017 will likely be a year of re-establishment for many vineyards, which means lower yields and fewer bottles produced. While this will impact us at Telaya, we have also been pulling fruit from Washington since our first vintage in 2008. Part of the reason for going through the trouble of making wine in two states was just in case something like a really, really harsh winter happened. We would still have long-established relationships (and contracts) with exceptional growers in the other area where the vines weren’t impacted.
WHAT TO EXPECT IN 2017
One thing is for certain, Idahoans have a way of banding together in the face of challenge. We’re lucky enough to be part of an industry that’s collaborative. Most of the people in the wine industry understand that the more outstanding fruit each vineyard can grow the more exceptional wine each winery can produce. Wineries producing exceptional wines benefit everyone by bringing more recognition and awareness to the thing we’re dedicating our lives to.
So, we expect you’ll be seeing a plenty of helping hands reaching out to assist our friends at the vineyards. Our wine industry is here to stay, and one rough winter won’t change that. In a few years, when we’re sitting around the fire and the winter of 2017 comes up, you may hear a few sighs before taking the next sip of exquisite Idaho wine.
3/11/2017 11:20:50 am
Earl, Very good article, explains what is going on with the vine during the stress of winter months on established vineyards. I hope Idaho can mitigate the damages from the winter of 2016-17. I feel the most critical item is establishing a vineyard is location, location, location! Using rivers to moderate the extreme temperature swings and using good elevation changes to help keep the air moving are site specific criteria for a vineyard to have a long and healthy life.
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