What is an own root grape vine?
01/09/2019
What is an own root grape vine?
Almost all wine grapes grown in Washington are grown on their own roots. That’s unusual. In most of the world’s other major wine regions, grapes are grown on grafted rootstock. That is, varietal stalks are grafted onto rootstocks resistant to phylloxera–a tiny sap-sucking insect–and nematodes–microscopic worms that may attack the roots of vines. Scientists are not completely sure why the phylloxera doesn’t exist in Eastern Washingon but they think the secret lies in the soils. They’re a happy, if cataclysmic, result of a series of Ice Age deluges—the Missoula Floods—that washed silt and sand across vast swaths of the region. After each successive flooding event, strong winds picked up the tiniest of the silty particles and blew them eastward, blanketing the landscape in a thick layer of fine sediment, called loess. Most of Washington’s viticulture happens east of the Cascade Mountains, and it’s utterly arid, a rain shadow zone, with fewer than six inches of rainfall each year. Nearly every vineyard must be rigged for irrigation, tapping into the local rivers for their moisture. The phylloxera can’t get going in the fine-grained powdery soils. This means that when the top of a vine dies back after one of the region’s hard winters, the new shoots that sprout from the base will be true to its genetic lineage. It also means that viticulturists can simply take cuttings from their existing vines and propagate them to make new ones, no grafting required. While hard to prove, most wine professionals believe that there is at least some purity of flavor lost in having two different vine types forged together. It makes intuitive sense that a vine would evolve its parts to work well together. Washington grapes are the same varietal from root to tip!
Post By:
Allison VanArnam