Driven by warmer temperatures, grapes are budding in Sonoma County vineyards

Buds breaking through on grapevines signals the arrival of spring - complete with colorful mustard plants growing between the vines - is nearing in Wine Country.|

Sonoma County vineyards have begun to show growth again, with the official start of the annual grape-?growing season dubbed bud break.

By late summer and fall, the vineyards will yield a wine grape crop that brought in an estimated $630 million in value countywide last year.

“The growing season has started and now we can talk about the 2020 vintage,” said Rene Byck, co-owner of his family’s Paradise Ridge Winery in Santa Rosa.

Unseasonably warm temperatures, including a record high 81 degrees in the city on Tuesday, caused the buds to burst early this year. Their arrival signals that spring - complete with colorful mustard plants growing between the vines - is nearing in Wine Country.

“It’s good news,” said Byck as he walked along the vines of his family’s Santa Rosa estate vineyard. A few chardonnay vines have swelled enough to burst through to become green shoots that will later bloom into fruit and hang until picked by crews in late summer.

It can take as long as six weeks to complete this process of rebirth throughout the nearly 60,000 vineyard acres in Sonoma County, depending on when the vines were pruned during the winter.

Bud break has historically started here in March, but it’s not unusual for it to begin in February like it did two years ago during a hot spell. In contrast, the 2019 buds showed for the first time in mid-March amid a colder and much wetter winter.

“Perhaps it’s the new normal,” said Jen Walsh, the winemaker at La Crema Winery in the Russian River Valley, of the early start to the growing season for the county’s top cash crop.

The North Coast grape harvest typically begins in mid-August for grapes that go into sparkling wine and can last through the first week of November for late red varietals. The early bud break could hasten the start of the 2020 harvest.

The Carneros region that borders San Pablo Bay is typically the first wine appellation to experience bud shoots on grapevines, given its milder climate, said Rhonda Smith, the viticulture advisor at the UC Cooperative extension in Sonoma County. In addition, hillside vineyard areas in the county with south- and west-facing slopes also usually are on the early side because of their longer sun exposure.

The La Crema vineyards in Carneros started showing buds last week, Walsh said, but that also occurred in the hilly areas of the Alexander Valley, and even in the Anderson Valley in Mendocino County with some young vines there.

Walsh has seen a lot of “popcorning,” an extreme swelling of the buds right before they burst and expects this to continue in the vineyards the rest of the week with the predicted warmer temperatures.

The one downside to the early start of the grape-growing season is that it provides another month for farmers and winemakers to guard against spring frost that could sweep through North Bay vineyards and potentially damage the grapes.

Mike Sullivan, winemaker and co-owner of the Benovia Winery in the Russian River Valley, already has started thinking about protecting the chardonnay vines from morning frost which could occur as late as May or even early June.

Benovia has five wind machines on its Martaella Estate Vineyard - planted to 42 acres of premium chardonnay and pinot noir - that rest in the Laguna de Santa Rosa, which can be more vulnerable to frost than its other properties at higher elevations, Sullivan said.

The machines will automatically start when the temperature nears freezing, but Sullivan said crews still go out to check to make sure they are working. In fact, the winery turned on one of its wind machines early Wednesday as a precaution because one of its vineyard sensors registered 36 degrees.

“It’s sort of unprecedented to have a multiple-week warming spell,” in February, Sullivan said. “It’s going to create a window for frost protection.”

Like other winemakers, Sullivan hopes for as uneventful weather year, after he and other North Coast growers in recent years have battled extreme heat spikes, wildfires and smoke taint risks. However, growers already are concerned about the dry winter in Santa Rosa, where no measurable rain has fallen - or is expected - in February for the first time since at least 1902.

Since Oct. 1, there has been only 15.82 inches of precipitation, about a third below historical rainfall totals for the nearly five-month period.

“We have had curveballs thrown at us,” Sullivana said, referring to the unpredictable weather.

You can reach Staff Writer Bill Swindell at 707-521-5223 or

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