Harsh winter takes heavy toll on Treasure Valley vines

Harsh winter damages Idaho grape vines

With the temperatures dipping well below zero over the winter, many southern Idaho grape growers are worried about extensive damage and a reduction in their grape output this year. This won't affect the quality of Snake River Valley wines, but it'
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With the temperatures dipping well below zero over the winter, many southern Idaho grape growers are worried about extensive damage and a reduction in their grape output this year. This won't affect the quality of Snake River Valley wines, but it'

Southern Idaho’s historically cold and snowy winter left devastation throughout Snake River Valley vineyards. It has also served as a poignant, painful and emotional reminder that viticulture is agriculture.

Cane bark (phloem) and wood (xylem) damage can occur in grapevines at temperatures from minus 4 to minus 13. Portions of the Treasure Valley crashed well below that.

At Williamson Vineyards in Caldwell, the family tracked two weeks of minus 18 temps.

Mike Williamson, a governor’s appointee to the Idaho Wine Commission, has taken the lead in getting the word out about the dire straits he and many of his fellow vineyard owners face.

“It could have been so much worse if we didn’t have 2 feet of snow blanketing the vineyard and protecting the rootstock,” said Williamson’s sister, Beverly Williamson-Mack. “We could be replanting all together, and that would set us back five years. Instead, we’ll be retraining from the ground up.”

She estimated the crop loss at 45-50 percent, which affects not only Williamson Vineyards wines, but also the dozen or so grape customers at other wineries. Those retrained vines will grow back and produce fruit for the 2018 vintage, but not this year. It’s a scene that will be repeated, with some vineyards facing 90-100 percent loss.

“People forget about the farming aspect of the wine industry,” said Moya Dolsby, executive director of the Idaho Wine Commission. “The grapes in the Lewis-Clark Valley came through fine, but this will be a light harvest in 2017 for Southern Idaho.

“Fortunately, something like this hasn’t happened in 30 years, but the 2016 harvest was one of the largest ever, and that’s going to carry a lot of people through. Who knew? We were pretty lucky with that.”

The skid of days in early January with below-zero temperatures threatened the young plantings by Sydney Nederend across her Scoria Vineyards & Winery, named the 2017 Idaho Winery to Watch by Wine Press Northwest magazine.

“Oh, my gosh, it was the worst winter in 80 years,” Nederend said. “In Huston, it got down to minus 23. Ours was only down to minus 12.6. Welcome to the fruit business.”

Site selection appears to have spared Scoria from total disaster.

“Sap is flowing and buds are swelling, which are good signs,” Nederend reported in early April. “We are planning on getting a crop this year, but it is hard to say how much.

“There is still some damage, but until bud break happens, we won’t be able to say exactly how much damage there is. Last year, bud break was April 9 in our vineyard, which was pretty early. I’m sure we are still a couple of weeks out.”

Stephanie Hodge, co-owner of Parma Ridge Winery, was in Maui when the damaging deep freeze draped across her 9 1/2 acres of vines.

“We’ll know more in the next two or three weeks, but we’re not going to be overly aggressive with our pruning until we know for sure,” Hodge said. “It’s amazing how some vines will repair themselves. We’re seeing sap flow, and some Chardonnay we took cuttings from is starting to bud out, so we don’t think we’ll have to cut everything to the ground.

“There is Zinfandel planted here, which is not an ideal climate for that, so I’m not surprised it’s toast.”

A key moment for the Idaho wine industry occurred in Washington’s Columbia Valley during January 1996. A freak stretch of 50-degree temperatures caused vines to wake up. Soon after, winter returned, down to minus 18 degrees. More than 50 percent of the Evergreen State’s vineyards were severely damaged.

Many grape growers cut down their vines and retrained them from their root systems. Those vines bounced back to produce grapes for the 1997 vintage, but they lost their crop for ’96. As a result, some of Washington’s most talented winemakers, including Rob Griffin, turned to Idaho for grapes and made stellar wine from Snake River Valley fruit. Those bottlings served as an “absolute lightning bolt” for Idahoans, Greg Koenig said.

“It was a watershed moment for the industry when Rob was making those wines,” Koenig recalls.

Earl and Carrie Sullivan of Telaya Wine Co. in Garden City continue to source fruit from high-end vineyards in Washington’s Columbia Valley. Jed Glavin of Split Rail Winery has been using the Yakima Valley.

A number of Treasure Valley producers are expected to follow them for the 2017 vintage.

Vizcaya Winery in Kuna, for example, plans to bring in Cabernet Sauvignon and Merlot grown in Washington by their nephew, acclaimed viticulturist Damon LaLonde, at his French Creek Vineyard in the Yakima Valley.

“Our vineyards were hurt just like everyone else,” Kay Hansen said. “We’re looking at taking at least 50 percent of our vines down to the ground.”

Eric Degerman runs Great Northwest Wine, a news and information website. Learn more about wine and see more stories at