Full impact of winter cold still unknown

by Karl Kazaks
While most Americans might look back on the winter of 2013-2014 as the year they became acquainted with the term “polar vortex,” vineyard owners and wineries and in the eastern and northern U.S. will remember the period for the repeated bouts of extremely cold weather.
“We know there is bud injury,” said Frederick Frank of Dr. Konstantin Frank, which has 120 acres of vines near Seneca and Keuka Lakes in New York’s Finger Lakes region. “It’s different depending on varieties and location.”
The USDA has even declared several counties in the region a disaster area due to the freeze damage (to both vineyards and orchards).
A survey conducted by Cornell University found significant primary bud damage across the Finger Lakes and Lake Erie region. In some parts of the Finger Lakes, said Tim Martinson, Senior Extension Associate in Cornell’s viticulture program, the damage is as high as 85 percent.
“Growers are responding by pruning differently,” Martinson said. Instead of pruning down to 30 to 40 primary buds per vine, they’re keeping up to four times that number, waiting to see which buds push before making further pruning decisions.
That’s what they’ve done at Dr. Konstantin Frank. “We trying to compensate for damage by leaving extra canes for extra buds,” said Frank.
The impact of the cold will be seen most in vinifera varieties, said Martinson. He expects the native grape varieties grown in New York, like Concord and Catawba, to show a modest impact, and the hybrid varieties a moderate impact. Even within vinifera there are different levels of hardiness, with Merlot and Pinot Noir being less cold tolerant than Riesling, for example.
Martinson’s assessment was echoed by Dennis Rak, whose Double A Vineyards is near Lake Erie.
“Our Concord has some injury but it’s not significant,” Rak said. The bud injury to his hybrid vines, he said, is more significant, and he expects the yield from them to “be quite a bit lower” than normal.
Double A also operates a nursery, offering about 100 grape varieties and shipping over two million vines a year. That business will also be impacted by this past winter’s cold weather.
While the vines he started last year had been brought inside prior to the freeze, Rak expects that next year there will be a shortage of certain varieties because he has been unable to get propagation material from all varieties due to cold injury.
David Whiting of Red Newt Vineyards on the south end of Seneca Lake doesn’t own any vineyards, but like everyone else in the Finger Lakes wine industry is looking forward to how the vines respond this spring.
“It’s kind of a wait and see thing,” he said. “It was a pretty rough winter, one of the coldest and longest winters I can remember.”
Growers in his area are seeing about 30 percent bud mortality, he said, which is above average but not as bad as in the upper parts of the Finger Lakes.
“Once the shoots come out and start going, we’ll know for sure.”
In general, according to Martinson, it appears that the vineyards further to the north and farther from the lakes will be most affected.
“It seems like the northern tip of the Finger Lakes has more damage,” Frank agreed, “but that’s a generalization.”
The most accurate generalization is that the impact across New York’s wine belt is varied.
“We had multiple low temperature events,” Martinson said. “Some areas got down to minus 16, minus 18 — several times — while others didn’t get below minus five.”
The full impact of the cold this past winter won’t be fully evident until the early part of the summer. By then, the stresses of the growing season will reveal whether a vine has suffered trunk or cane injury.
The success of the 2013 harvest — both in terms of quality and production — will be something growers in the Finger Lakes can rely on if their 2014 crop comes up short.
Hilling up vines to protect the graft union — and basal bud — is another kind of insurance for vinifera growers throughout upstate New York. If it turns out the vine has suffered trunk damage, growers will be able to train the basal bud into a new trunk. That’s what they’ve been doing at Dr. Konstantin Frank for 50 years, retraining vines after cold winters, thus making their vineyards some of the oldest in the entire U.S.
“I’m expecting there will be a lot of trunk renewal going on this year and next year,” said Martinson. But probably not as much as followed New York’s last severely cold winter — 2003-2004 — because, at least in New York, the extreme freezes weren’t proceeding by above freezing temperatures (just more moderate levels of cold).
In Ohio, though, the damage from the winter cold is expected to be much more severe, possibly the worst on record. Almost the entire vinifera crop may be lost, and more than 50 percent of the crop from hybrid varieties may also be lost. They even expect production from native varieties to be down by over 25 percent.
As elsewhere, it’s too early to tell how much of Ohio’s vineyards suffered trunk damage, but the losses are expected to be impactful — 20 to 30 percent.
One of the reasons experts expect Ohio to have significant numbers of vines with trunk damage is the cold polar vortex area was preceded by periods of warm weather, leading the vines to deacclimate.
As of mid-April, vines in the Finger Lakes hadn’t deacclimated too much, said Martinson. Researchers there test buds throughout the winter to measure deacclimation and, thanks to cold spring temperatures, vines haven’t started to lose their cold-hardiness.
The slow start to spring in New York’s wine region brings its own concerns. Will there be a late bloom, and if so, will the growing season be long enough and warm enough to get fruit ripe?
“The later the bloom the more difficult it is to get the crop right,” Rak said.
Frank concurred, noting that the ecosystem in the Finger Lakes was still quite cold as of mid-April. “A very hot summer could compensate for a delayed bud break,” he said, “but most likely the growing season will be shortened. The jury’s still out.
“The good news is there’s very little chance of spring frost when you have delayed bud break.
“It’s kind of wait and see at this point.”

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