Why Vines Turn Color

Hallberg Vineyards, Graton, Sonoma County (11/13/20) David Laurence Sharp

Rain is diluting the color seen in California’s vineyards, but only momentarily.

We’ve found that unless the leaves are blown off, they usually retain their color following storms. And, the current storm, though it will last, off and on, for a week, it appears to be light, so far.

Doug Stanton of Stanton Vineyards in St. Helena says a greater danger to the leaves is frost. Freezing temperatures will quickly turn leaves brown that will drop to the vineyard floor. He urges going now to see the vines at peak, as with the rain and possible frost, the show could be gone by the end of the month.

The Stanton family has been growing vines in the Napa Valley for 73 years (Doug for 30); they also produce 500 to 800 cases of wine each year.

Bright reds and oranges are not something that’s a good thing. The colors indicate the vines are diseased, which delays ripening. Stanton explains, “Really colorful vineyards didn’t start with clean material.” This occurred because, historically, vineyards were planted from cuttings taken from other blocks which spread disease. Today, vines come from nurseries that certify their stock as disease free.

Disease doesn’t necessarily affect the quality of a wine, but it does reduce the productivity of the vineyard. Stanton explains, “Years ago, wine makers would say, ‘we don’t mind a little disease. It adds character.’ Though, as a grower, I want them disease free, so that they’ll ripen as quickly as possible, before it rains.”

Planting a vineyard is a big investment. Stanton says, “certifying you’re using clean material is the most important decision a grower makes. We want a block to be producing 20 to 30 years or more.”

As such, scenes of brightly colored grape leaves, such as that above – taken in Calistoga a dozen years ago – may soon disappear. The removal of unproductive vineyards is occurring throughout the Napa Valley. Stanton says, “They’re culling the vineyards, right now. You’ll see lots of empty fields with vines, that were no longer producing, heaped up.”

As diseased vines are removed, healthy ones which display bright, yellow and lime-colored leaves are replacing them. That does not mean shots like that above won’t be found. Diseases will always infect vineyards, but more vineyards will be uniformly yellow and green.

A lot of media attention was given to the effect of recent wildfires on wine production. About 30% of the harvest was lost due to buyers assessing the grapes as being “smoke tainted.” Other than the loss of a sizeable part of this year’s harvest, Stanton explains that the smoke did little long-term damage that won’t be blown, washed and pruned away during winter.

As to when grape varieties show fall color, Stanton agrees with wine country photographer David Laurence Sharp who observes that early ripening vines, such as Chardonnay and Pinot Noir, tend to show peak fall color earlier than late ripening varieties.

Sharp says the Alexander and Dry Creek valleys in northern Sonoma County are planted with later ripening varieties, whose leaves, he estimates, will turn later this month.

Stanton’s favorite places to see fall color in the Napa Valley have been the Oakville grade, Far Niente (whose grounds are beautifully landscaped), White Sulphur Springs (though areas were burned in recent fires) and west of St. Helena.

My favorite? Well, since I’m not a grower, any diseased vineyard.

  • Vineyards, Sonoma County (108′) – Near Peak (50-100%) Go Now.
  • Vineyards, Napa Valley (253′) – Near Peak (50-100%) Go Now.