Impacts of winter cold being felt in vineyards
With an exasperated sigh, Colorado state viticulturist Horst Caspari grabbed at yet another untrimmed grape vine hanging from a trellis and wove the emerald fuse between two wires.
“I know there won’t be many grapes this year in most of these places, but that’s no excuse not to be out here taking care of the vines,” said Caspari, midway through a morning tour of several Grand Valley vineyards on East Orchard Mesa. “You have to spend time in the vineyards this year so you get a good crop next year.”
Valley grape growers are finding this summer a re-run of 2010, when many vineyards were regrown after being killed to the ground by a Dec. 2009 freeze.
Growers again this year are letting most of their vines go wild, building vigor, storing nutrients and growing new branches (canes) to replace those lost to winter cold.
While it lessens the time (and money) owners spend this summer in the vineyard, Caspari said effort now means better production in the future.
“In 2011 we did OK but didn’t have (the grape crop) we should have,” he said. “That’s because (grape growers) didn’t do a good job of retraining the vines in 2010.”
He looked at the dense foliage splayed before him. “This is all this year’s growth and next winter you just re-establish the complete framework,” he said, holding up a handful of new shoots. “But you don’t just lay it down and let it go.”
Last January, shortly after a valley-wide freeze sent temperatures as low as minus 21 degrees, Caspari guessed grape growers this year would see a 75-percent grape loss.
Recent surveys indicate the loss may not be that severe but we saw a lot of leafy but empty vines.
Caspari said the January cold and an April frost that reached 20 degrees was too much for many of the favorite grape varieties.
Merlot seems to have been particularly hit hard across the valley, along with syrah and gewurtztraminer.
“If you can grow Merlot this year, you’ll sell every bit of it,” Caspari said. “Good location is the key.”
“You try to scientifically get your head around it but it’s impossible,” said grape and peach grower Neil Guard at Avant Vineyards on East Orchard Mesa. “You’ll have three plants that have grapes and four that don’t, all within 50 feet.
“I think my Cabernet Franc, Riesling and my Petit Verdot look fine, absolutely just a normal year,” said Guard. “There’s no rhyme or reason to the damage we see.”
As Guard noted, Cabernet Franc, a red grape known for its cold-hardiness, came out of the winter in good shape in most places while Riesling leads the white varieties.
Another challenge facing growers this year is uneven ripening after the late freeze and a cool spring in some places delayed bud break.
“Look, these won’t ripen,” said Caspari, holding a vine bearing several clusters of grapes, each berry tiny and hard, no bigger than a pencil eraser. “They are at least two or three weeks behind now, and all they do is steal nutrients and vigor from the other grapes.
“What’s bad is they will change color so the pickers can’t tell them apart from the ripe grapes,” he said. “But they’re green and they’ll add off-flavors to your wine. They have to go.”
And he started tearing away the green berries, moving vine to vine and throwing the pre-mature clusters on the ground.
Caspari stopped midway down a row of grapes, looking ahead at the hours of work awaiting some vineyard worker.
“There’s an old saying that the thing you want to see the most in the vineyard is your shadow,” he said. “I don’t think people understand how critical it is to train your vines this year in preparation for next.”