Mediterranean breezes, California sunshine— what’s not to like for a vinifera grape growing in one of these spectacular regions? But what about Missouri and its humidity, fluctuating winter temperatures, hot summers, late frosts and hail? Truth be told, it’s pretty amazing that Missouri is home to so many vineyards.
“Missouri has a very challenging climate, and you’ve got to be passionate about this industry to grow grapes here because it’s a lot of work,” says Stone Hill Winery GM Jon Held, whose family has owned and operated the winery since 1965. “Traditional grapes like cabernet sauvignon, chardonnay and pinot noir are European grapes,” he says. “The original source of vinifera grapes is the area around the Mediterranean, and that’s why they thrive in California, which has a similar climate. Missouri has a continental climate— characterized by cold winters, hot summers and, complicating that further, plenty of rainfall during the growing and harvest seasons, causing fruit crop to rot.”
According to Held, it’s all in the type of grape grown. “We have to grow varieties that are either hybrid or indigenous,” he explains. “The real problem with Missouri is we can have a 60-degree day in the middle of January and then the next day, it could be 5 degrees below zero. That situation is devastating to a grapevine.” He adds that when it warms up, the vine will start to declimatize or ‘wake up,’ thinking that spring has arrived. But grapes that have evolved in this climate can survive what he calls ‘roller-coaster ride temperatures.’ “The norton, for example, just goes and grows right along.”
And then when there’s an early spring, further challenges can develop. “With it being so warm so quickly this spring, the vines budded out about a month early,” notes Randy Hamann of Weingarten Vineyard. “It presented a greater chance for frost, which we did have. Fortunately, we didn’t get hurt because our vineyard is located at a higher elevation.”
Rather than looking at the macro climate of Missouri, it’s the micro climate of an individual vineyard that is critically important, Held says. “The main criteria for location is that the vineyard be situated on a real high hilltop that has good drainage with deep valleys around it, so when the cold air comes down during a frost, it continues to drop off into the valley and pull warm air from above onto the vineyard,” he notes. “With the late frost that we had, every one of our vineyards escaped damage.”
Hamann indicates that another fear of grape growers in Missouri is extremely frigid winters. “We haven’t had a really cold winter since we began eight years ago,” he says. “We have not had the type of sustained cold that we use to have in the 1970s and 1980s when it would get below freezing and remain there for five or six weeks. Everyone is getting spoiled because we’re all out doing this vineyard thing, but we could get totally wiped out if we have an especially bad winter.”
Currently, the thought on growers’ minds is not on the 2012 vintage, but rather on the 2013 vintage. “Right now, we are creating next year’s crop within the grapevine, so any climatic stress that occurs to that grapevine can affect next year’s crop,” Hamann explains. “The drought that we’re currently having across the state can affect next year’s fruit crops, and I’m worried about not having any crop for 2013. The climate is absolutely key to just about everything we do.”