Weed Control is a Year Round Task in any Vineyard

For most vineyards here in Napa, California and certainly across the Western U.S., weeds are a reality that every winegrower must either control or manage. The largest group of weeds by species are winter annuals and like most weed species they have an extraordinary capability for growth, survival and competitiveness for space, light, water and nutrients.

In Napa vineyards these winter annual plants germinate in the fall, grow low to the ground through the winter, and then grow and bloom at a rapid pace in the spring. By early summer they are pretty much done growing, set seed and dry up.

Most of these weeds are manageable for vineyards and some growers manage them as a self-reseeding cover crop by mowing whatever happens to grow between their vines. The weeds will grow when vines are dormant and are often actually helpful in preventing soil erosion. Examples of weeds that are not difficult to manage in a vineyard setting would be mustard, filaree and annual broome grass.

But as you might imagine with weeds, problems are never too far away! When they grow at the same time as the crop, difficulties arise due to the weeds competitive nature. Of course vineyards will mow, spray and cultivate weeds to make sure they don’t grow at the same time as the vines and they have to be kept under control to reduce habitat, food and shelter for rodents. The other reason for keeping a clean and cultivated vineyard is because here in Napa we simply like how they look!

Like any other aspect of our lives, technology is having an impact on how winegrowers manage the weeds in their vineyards. There is a growing trend toward environmentally conscious weed and pest control through the use of propane generated heat, with applications of either flame or steam. These two methods are an alternative to chemical application and mechanical cultivation, and are both recognized by the U.S. Department of Agriculture National Organic Program.