Varietal Considerations for Desert Locations
or
So You Want to Plant Some Grape Vines?
or
So You Want to Plant Some Grape Vines?
There's an ideal range of elevations for growing wine grapes in Arizona.
Depending on location, from about
3,000 feet up to around 5200 feet, most varieties thrive. In this range
wildlife with a taste for grapes are generally the biggest problem. Above this range short summers and late spring frosts make growing grapes difficult, but not impossible. Many books have been written on the topic of cold climate viticulture. However, if you're below 3,000 feet there's little information available. Table grapes have a long track record in the lower deserts, but there just hasn't been much interest in growing wine grapes at these elevations. Frankly, many have assumed that it wasn't possible. There are some significant challenges in the lower deserts. The intense mid-summer heat and low humidity can cause grapes to dessicate or sunburn, acidity to drop too far, and grapes to ripen too quickly, leaving color and tannin lacking. Our mild winters aren't cold enough to provide an adequate dormancy period which can cause uneven ripening and impact fruit quality. And in some locations monsoon rains can promote fungal diseases. Although not much has been published about desert viticulture, there are some recommendations to consider. The Master Gardener program at the University of Arizona recommends Barbera, Petite Sirah, French Columbard, Emerald Riesling, and Sauvignon Blanc. One can also look to southern Europe for ideas. Varieties from Italy, southern France, Spain, and Portugal are good candidates. There are likely several good desert grapes among the thousands of varieties indigenous to Greece. Unfortunately, the quarantine requirements make importing new plant material difficult. The search for an ideal desert grape has taken some in the direction of hybrid and native varieties. Experimental plantings of Léon Millot in west Texas and Clinton in Scottsdale have both done well. These varieties ripen so early that they miss much of the heat. Black Spanish, an accidental hybrid, is favored by some desert growers as well. Despite these successes, native and hybrid grapes don't always thrive here and some exhibit undesirable characteristics. For example, Concord Seedless produces small seeds when grown in our heat. If you're looking for a good table grape, Thompson Seedless reigns supreme. Flame Seedless does well here as well, and if you want a native (Concord like) variety, Mars Seedless is showing promise. Generally wine grape varieties that are well suited to the lower deserts have:
But some varieties seem to do well here without a dense canopy. Their grapes continue ripening slowly without showing signs of dessication or heat stress. This may be due to the thickness of the skins, the size of the berries, or the ability of the vine to stay ahead of transpiration. Among those that seem to hold up well are Petite Sirah, Syrah, and Cabernet Sauvignon. Cabernet is an unusual grape for the desert and a wine made exclusively from it would likely not compare well to one from a more moderate climate, but in limited trials it has ripened well with few issues. In some respects white wine grapes can be less problematic. Uneven ripening can cause a few green or raisined berries at harvest, but with whites this may actually add a bit of complexity. The heat may however reduce volatile aromatics, those molecules that make a wine smell and taste so good. Not surprisingly Muscat is a popular grape in desert vineyards; It's likely the most aromatic white grape on the planet. Low acidity can be a real problem with many varieties. Of course this can be addressed pre-ferment by the addition of tartaric acid, but a number of desert grape growers are trying Barbera for this reason. This is a red grape from Italy that's known for producing high acid wines, and the early results here are good. We may never find an ideal desert wine grape. Ultimately we may need to develop blends that mitigate issues with desert grown grapes. Some varieties, like Grenache and Nebbiolo do well here, but they can be severely lacking in color. Tempranillo loves the heat and produces dark, flavorful fruit, but the acidity can be far too low at harvest. Blending may provide a solution. In time we may find several wine grape varieties that out perform all others, or we may develop our own outstanding blends, but already there are a number of varieties that are showing good results. For more information please visit www.azwinemakers.com. Optional Images  Ripening Nebbiolo grapes in the lower deserts of Arizona.  Cabernet Sauvignon can handle the heat. (althernate)  .Tempranillo has a long track record in southern Europe.  Barbera, a promising variety for desert vineyards. (alternate) (Barbera photos courtesy of Brett Cook.) |
