Fall freeze weighs on Idaho wine industry

By on February 18, 2015
The mid-November Arctic blast that sent temperatures below zero in parts of the Snake River Valley has some vintners and growers worried about the 2015 harvest.

The mid-November Arctic blast that sent temperatures below zero in parts of the Snake River Valley has some vintners and growers worried about the 2015 harvest. (Photo by Eric Degerman/Great Northwest Wine)

BOISE, Idaho — Those frigid mid-November conditions that allowed Pacific Northwest winemakers to pick early for ice wine now have some in the Idaho wine industry worried about the 2015 vintage.

The Idaho Wine Commission’s annual industry meeting begins today at the Boise Hotel and Conference Center, and while wine economist Mike Veseth serves as the keynote speaker, a topic of discussion outside of the Cascade Room will be possible vine damage suffered last fall.

Grape grower Dave Daniel fears trunks may split throughout his 4-acre vineyard, which sells Merlot grapes to three Snake River Valley wineries. A similar hard freeze wiped out his Nampa site in 2013.

“That year, it was in January when we got into the negative territory for three straight mornings,” Daniel said. “This was so much different because it was in November. The vines hadn’t even shut down yet. Some of them still had leaves on.”

From 65 to sub-zero in 2 weeks

Wine grapes get a layer of frost in Washington wine country.

A few leftover grapes pick up specks of frost in the Yakima Valley. (Photo by Andy Perdue/Great Northwest Wine)

At the Bureau of Reclamation’s weather site in Nampa, the temperature reached 65 on Halloween. On Nov. 16, it dipped to 1 and tumbled below zero the next two nights. Daniel focused some of his attention on Washington State University’s AgWeatherNet during that time.

“I watched their cold-hardiness site based in Prosser, and the damage point was 5 or 6 degrees,” Daniel said.

Daniel sells to Indian Creek Winery in nearby Kuna as well as Boise-area wineries Cinder and Telaya Wine Co.

“Nobody is really sure what is going to happen until April or May, but all of the data indicates an event happened that could be pretty detrimental,” said Telaya vintner Earl Sullivan. “I’m working on getting backup sources in Washington for all the varieties that I pick in Idaho.”

Telaya sources about 20 percent of its grapes from Columbia Valley vineyards such as Boushey and French Creek, but Sullivan said he may need to branch out into Washington for as much as 50 percent of his fruit this fall.

“We don’t have a lot of fruit options in Idaho,” Sullivan said. “I want to be consistent though because I don’t like to tell my growers in Washington that I want 50 tons one year then ask for only 20 or 30 tons the next year.”

Damage won’t be revealed until after bud break

Red Mountain bud break

Head-pruned Syrah grapes begin to awaken from their winter slumber near Hedges Family Estate on Washington’s Red Mountain. (Photo by Andy Perdue/Great Northwest Wine)

By Mothers Day, Daniel hopes to know if his vines are limited to some bud damage or face a catastrophic trunk split. Vine collapse prompted him to cut down almost all of his vineyard in spring 2013.

“We generally will bud out about the third week of April,” Daniel said. “But in 2013, when things started budding out, I couldn’t tell if it was a primary, a secondary or tertiary bud that popped. Until they start flowering — or don’t start flowering — it’s really tough to tell.”

Research published last year by WSU scientist Michelle Moyer and then-Penn State researcher Mark Chien, now at Oregon State University, wrote that vitis vinifera is “very sensitive to low winter temperatures and rapid changes in temperature.”

“Normally, we very rarely get a heavy frost until the end of October or the first week in November,” Daniel said. “By then, the vines have slowed down and shut down because we’ve cut the water back. This year, we had a pretty mild start to November. The vines just wouldn’t quit, even though we cut the water back.”

Sullivan said he and a number of other winemakers asked growers in the Snake River Valley to hold off on picking a significant portion of their clusters until the third week in October. That also would shorten the window for vines to harden off adequately.

“It was a pretty hot summer, so I let some fruit hang longer to get flavors to develop further,” he said.

However, picking at Daniel Vineyard — a 2,600-foot elevation site first planted in 1998 — wrapped up on Sept. 17. That gave those tender vines more than a month of post-harvest recovery time and a chance to harden off.

“Cutting out and retraining vines is horrible,” Daniel said. “It’s tough enough to establish a vineyard from original rootstock, but when you cut them off, they just go nuts after that. We got 10 to 15 shoots per plant, when normally they are down to three or four shoots. It was quite a scene.

“We had a wonderful crop last year for their first year back,” he added. “We got 3.6 tons per acre, and the fruit was fantastic — amazing balance for as out of balance as the vines where.”

Daniel said those few trunks he didn’t chop down in 2013 seem to be on a long path to recovery.

“I did leave about 12 plants, and they’ve been behind the others ever since,” Daniel said.

“They ended at about 1.8 tons to the acre, but the fruit was pretty crappy. Those vines still haven’t recovered from the vascular damage to the trunks and cordons. There’s a lot to be said for youth and vigor rather than old age and experience.”

Damage from 2013 blast not widespread

A number of Idaho winemakers feared the 2013 damage would be more widespread, and there have been several brushes with extensive damage throughout the Snake River Valley in the past 30 years. Indian Creek suffered large amounts of trunk damage in 2007, but that was a relatively isolated case.

“I’ve been growing myself since ’98, and we’ve really not had a huge winter event since then,” Daniel said. “In ’91, there was an almost total freeze out, and everybody cut down to the ground.”

It’s been nearly 20 years since the killing freeze of 1996 in the Columbia Valley sent a number of Washington winemakers to the Snake River Valley — and beyond — for grapes.

This year, Daniel is optimistic that projections out of Prosser by WSU will be accurate.

“Prosser predicted that about 10 percent of the primary buds will be damaged,” Daniel said. “If it’s no worse than that, we’ll be very happy. I can’t see that we would cut back like we did in 2013. We’ll just ride out what we can this year.”

In the meantime, skies are clear and sunny in the Snake River Valley for the annual Idaho wine industry meeting.

“Now we’re having days in the 50s and it’s February,” Daniel said. “It’s going to be a wild year. Well, it already has been a wild year.”

About Eric Degerman

Eric Degerman is the president and CEO of Great Northwest Wine. He is a journalist with more than 30 years of daily newspaper experience and has been writing about wine since 1998. He co-founded Wine Press Northwest with Andy Perdue and served as its managing editor for 15 years. He is a frequent wine judge along the West Coast and contributor to Pacific Northwest Golfer magazine, the region's longest-running golf publication.

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