Winegrape vines sprout in Sonoma, Napa, Lake counties

Following on recent sightings of winegrape vines springing back from a winter nap in Sonoma County, Napa Valley and Lake County growers are reporting vines are budding or soon will be.

Warm temperatures and relatively little recent rain have brought on the start of the 2016 winegrape season, a stage called bud break, according to Jennifer Putnam, CEO and executive director of Napa Valley Grapegrowers, a trade association with more than 690 members.

During this phase, vines awake from dormancy and begin to push water up from their roots. Tiny vine buds that formed from the prior season begin to swell then break open with shoots. From these shoots come leaves that help accelerate growth, especially as temperatures warm.

Growers and vintners are quick to point out that vine development this early in the season may not say much about the resulting vintage. They point to last season, in which high winds and showers during the critical vine pollination stage cut resulting grape yields by double-digit percentages.


Sonoma County growers and vintners reported seeing bud break on early-ripening varieties — pinot noir and chardonnay — in the latter half of February, following on course with the pace of previous seasons. Their Napa Valley colleagues seeing signs that this stage of the season might be coming earlier.

'Buds on chardonnay have begun swelling and bursting on a few vines,' said Brittany Pederson, viticulturist at Silverado Farming Company and a member of the trade group.

The pace of this season seems faster than that of other years.

'From what we are seeing throughout the valley, in comparison to last year, we are anticipating possibly about five days to a week ahead of schedule with bud break,' she said.

Matt Reid, winemaker at Benessere Vineyards, said bud break is coming much earlier than normal even earlier than last year.

'We have no bud break yet, though apical buds are in the 'popcorn' stage, which usually proceeds bud break by a handful of days.'

'I'd say we're a good week to 10 days ahead of last year and about 17–21 days ahead of normal,' he said at the end of February.

While other Napa Valley growers await bud break, their crews are busy pruning, managing wild and cultivated cover crops and watching vine development.

'Our cover crop is doing nicely,' Reid said. 'We are using a mix of oats, fescue, peas and favas, and we have a lot of volunteer mustard providing lovely color.'

With the arrival of bud break, grapegrowers typically keep a close eye on nighttime temperatures and prepare for the threat of frost, which could damage the delicate shoots at their most vulnerable stage, Putnam said. Heavy rain could also hurt young shoots.

Up to 2 inches of rain was forecast for Napa Valley in a storm expected March 4–6 and another inch or two in rain is anticipated March 10–12.

'We are happy with the frost forecasts, but somewhat concerned about heavy rain in the forecast,' Reid said. 'Similar to last year, we have a full soil moisture profile and our reservoirs in Napa Valley are full. More rain would be great for vineyards and the environment in general, but we'd prefer to see it after the shoots have established themselves a bit more. The long-term forecasts suggest we may get rain in late March and early April. That could help keep the frost risk low.'


Spring for grapevines in higher-altitude Lake County may be emerging. Clay Shannon hadn't seen or heard of bud break on the 1,200 acres of vines Shannon Ridge Vineyards farms in Lake County, with 360 acres in the Red Hill appellation, 150 in Kelseyville and about 800 in the High Valley district as of March 2. But he said there's 'a little swelling on hilltop early varieties.'

'I thought it was going to be real early, but it cooled off again,' Shannon said. 'And now things look to be pushing only slightly early but still later than last year, which is good.'

Though rainfall on Shannon Ridge properties is behind where it was last season, he's optimistic about the forecast.

'I am hoping this weekend storm will even us up with last year, which would be great but still not at average rainfall,' Shannon said. 'Frost is always a concern. Heavy rain won't hurt us right now. And, so what? We need the rain!'

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