Steady warming trends may eventually make it impossible for now-premium regions to grow popular varieties like Cabernet Sauvignon and Pinot Noir. Scientists writing in PNAS, a journal published by the National Academy of Sciences, warn that human-induced climate change could shrink winegrowing regions as much as 85% by 2100—unless the trend is turned around and vintners expand the range of grapes they grow.
Thankfully, grape breeders like Dr. Andrew Walker of University of California, Davis are responding to the challenge. In 2019, Dr. Walker released five new disease-resistant grapes—the first release of new grapes from Davis in decades. One in particular has California growers excited: Ambulo Blanc.
This white grape is 97% Vitis vinifera, a cross of 62.5% Cabernet Sauvignon, 12.5% Carignane, 12.5% Chardonnay, with the remaining percentage split between two Native North American species, Vitis arizonica and Vitis rupestris.
“Ambulo Blanc was released to nurseries first, and it’s now being planted in vineyards across California and in the southern U.S.,” Dr. Walker says.
Ambulo Blanc was bred with the goal of producing a premium wine grape that could also resist Pierce’s Disease (PD). The disease is caused by the bacterium Xylella fastidiosa, spread primarily via sharpshooters, a vector insect that thrives in warmer climates. Wine, table and raisin grapes are all susceptible.
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Tom Gamble, third-generation farmer and founder of Napa’s Gamble Family Vineyards, planted one-eighth of an acre of Ambulo Blanc in the Yountville subappellation of Napa in 2019. So far, he’s thrilled with the results.
“We planted it along a creek on the perimeter of our Sauvignon Blanc vineyard,” Gamble says. All told, Gamble has 175 acres under vine in Napa. “The sharpshooters are really active along waterways, and we found that by planting those grapes there, we gave them what they needed, and they didn’t fly into the vineyard.”
But the PD-resistant grapes are doing more than just acting as Gamble’s vineyard soldiers.
“Our vines are only three years old, but I’m loving what we’re getting from them,” Gamble says. “The small batches we’ve made have tannin and grip, with earthy and floral aromas, fresh flavors. It reminds me of Sauvignon Blanc. The texture is unique and compelling, and the acids are great. We have been vinifying Ambulo Blanc in neutral French oak every year, and at this point, we see it as interesting in a blend.”
It’s too early to tell what regions and soils Ambulo Blanc will thrive in, but according to Walker, it is growing well—and combatting PD—wherever it has been planted, including Temecula, Sonoma and Napa. Other producers, including Rutherford’s Caymus Vineyards and Oak View’s Ojai Vineyards have bottled the wines experimentally, and may release them in the future.
In the glass, Walker and Gamble agree, Ambulo Blanc delivers citrus, lime, gooseberry, Golden Delicious apples—what Gamble dubs a “worthy, food-friendly, everyday wine.”
Quick Facts
- Grape: White
- Crossing Of: Cabernet Sauvignon, Carignane and Chardonnay
- Where Grown: California and Southern U.S.
- Wine Styles: Single-varietal and blends
- Aromas/Flavors: Citrus, lime, gooseberry, Golden Delicious apples with slightly bitter texture
- Food Pairing: Spring vegetables, seafood dishes and a variety of spicy cuisine
This article originally appeared in the October 2023 issue of Wine Enthusiast magazine. Click here to subscribe today!
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Last Updated: September 8, 2023
