A relentless winter with dangerously low temperatures has killed vine buds and wiped out a significant portion of this year's potential wine grape crop in parts of the Finger Lakes, Ontario and Michigan. Growers are assessing the damage and hoping to coax the most fruitful growth possible out of surviving plant material in the spring. But they fear the cold may have killed some vines too.
"I don't know about you, but it's been sunny and 70 up here most of the winter!" joked Tom Higgins, owner of Heart & Hands Wine Company in New York's Finger Lakes. As residents of the Northeast and Midwest know, it's been anything but in recent months as temperatures reached repeated lows below zero, even as low as -29° F in some growing areas. The weather severely tested vines in cool-climate wine regions. Some areas suffered nearly 100 percent bud damage on vinifera vines—a potentially disastrous loss in crop.
Vinifera varieties can usually shrug off cold temperatures during winter dormancy, but depending on the grape, the region and the duration of the cold snap, buds start dying at between -8 and -14° F. Among the common varieties in the regions hit, Merlot and Sauvignon Blanc suffer more readily than Riesling and Cabernet Franc. When buds die, crop is obviously reduced. Secondary buds may grow later, but these are less fruitful.
And the damage might be worse. Dead buds mean one bad vintage; dead vines take years to replace. "Over 50 percent bud injury in a certain variety, then we start to think there's going to be some trunk injury," said Hans Walter-Peterson, a professor with Cornell's Viticulture and Enology program who has analyzed 12,000 cane samples in the Finger Lakes so far this winter. "Is it enough to kill the vine?" That's the big unknown. "Think of [a vine's vascular system] as a bunch of straws. If you gum up enough of those straws, the vine can't pull up all the water and nutrients that it needs, and it can collapse." Healthy-looking vines may be dead inside, but won't keel over until the stress of summer.
"There are vineyards that I've heard of, [where the owners are] looking at taking a bulldozer at this point and starting from scratch," said Higgins. It can offer an opportunity to replant to cold-hardier varieties—past hard freezes led more growers to plant Riesling in the Finger Lakes. "It may also allow people to rethink, 'Am I in the right business?'" said Higgins. "Maybe the dream of growing grapes for some of these people has worn off."
The cold and its crop reduction come at an inconvenient time, as public thirst for these wines continues to grow. Higgins worries that just as consumers are starting to look for Finger Lakes wines, they'll see store shelves filled with wines from other regions that didn't get hit by this winter.
Michigan and Ontario, increasingly recognized for their vinifera wines, also saw difficult conditions. "Having maintained a consistent cold temperature combined with ample snowfall has helped us a little because the vines never woke up," said Eddie O'Keefe, president of Chateau Grand Traverse in Old Mission Peninsula in northwestern Michigan. "We are cautiously optimistic."
Duke Elsner, director of the Michigan State University agricultural extension in Traverse City, has been examining samples from around northwestern Michigan. He saw some damage on Riesling—17 percent primary bud death. "Cabernet Franc, one of our leading reds, looks bad," at 60 percent, he said. But because growers have not pruned yet, "I don't see enough of a loss that we can't carry a good crop."
In the two southwestern Michigan appellations, the ending may not be so happy. Twice in January, it hit -13° F. "After this very low temperature, we lost the lake effect. All the mitigation in the temperature just went away because [Lake Michigan] froze over," said Paolo Sabbatini, another MSU researcher who has been taking samples in the south. He puts the average at 70 to 90 percent primary bud damage. (Native and hybrid grapes fared better, and they are also more fertile on their secondary buds.)
"This year's been like a prizefight. It's not the first punch that gets you. It's getting punched over and over again," said Kevin Ker, a viticulturist associated with Brock University's enology program in Ontario. He predicts Ontario will produce about 60 percent of a normal crop, with Niagara "spotty" and southwest Ontario decimated.
What's next? Sabbatini strongly advises growers with vineyards suffering high damage to wait until spring to prune, and to leave more canes and spurs, thus giving more buds the chance to blossom.
Long Island and Virginia largely escaped the cold damage suffered by other eastern regions. But "the patterns that we're seeing where we have fairly warm temperatures for a few days and then pretty nasty cold temperatures don’t appear to be modulating at all," said Tony Wolf, viticulturist at Virginia Tech. "I'm a little concerned about the potential for spring frost. That’s the next hurdle we have."
But up north, growers like Michigan's O'Keefe are still looking at a foot of snow on their vines. "It's still full on winter here," he said.