This quarter I have decided to spotlight one of the least talked about categories of wine production, root stock. In fact, the subject of root stock is so obscure that when I called the wineries to discuss the topic their marketing people could not answer more than my most general questions. Eventually they turned me over to their winemakers and vineyard managers, and even they were baffled by my interest, but humored me nonetheless. I hope you find this topic as interesting as I do, and if so, let me know what you think.
The first thing to know is that the root stock is the part of the plant that grows underground. If you ever look at a grape vine, or many other plants like roses and citrus trees, you will see what looks like a knot in the trunk a few inches above the ground. That is the scab that develops when the root stock is grafted to the actual plant, called a scion. In essence the scion borrows the root stock to absorb nutrients and water from the soil. There are many reasons why root stocks are now used, although the most common is for pest resistance. Each wine selected this quarter will demonstrate the need, or not, for root stock and how that effects the growth habit, farming and styles of wines produced.
To understand why root stocks are important let’s look at the French wine industry in the 1850s, and how within 40 years the country’s production was almost wiped out. It all started when English botanists imported grape vines from America for their cool climate gardens. Unbeknownst to them the vines they brought to England also carried on their roots an aphid called phylloxera. The vines from the US had developed resistance to phylloxera and were unaffected by its presence, but that was not the case for the vines in Europe. This is because all grape vines are the same genus, vitis, but there are more than 60 different species. The most common species in North America, vitis labrusca, vitis rotundifolia and vitis riparia have all developed resistance, but the species of Europe, vitis vinifera has not. Once the aphid landed in France in the 1850s the all-you-can-eat buffet was open and phylloxera came hungry.
To put the devastation into numbers, by 1878 more than 25% of all the vines in France were dead or dying of phylloxera. For many years the growers had no idea why their vines would shrivel and die, but by the 1860s the culprit was discovered. In defense the growers attempted to drown the little buggers by flooding their vineyards, others injected noxious, poisonous gas into the ground around the vines. Nothing worked until 1870 when a Missourian named Charles V. Riley theorized the solution, that the French vinifera vines could be grafted to resistant rotundifolia and riparia root stocks, which worked. Unfortunately the French, and other Europeans, were slow to adapt this solution fearing the wines would taste like their foxy, funky rootstock varieties. Thankfully by 1890 most regions began adopting root stocks, but not before half of all the vineyards in France were destroyed. France was not alone, by then phylloxera had devastated almost all the vineyards in Europe, except in areas where the soils were inhospitable to the louse. Today almost all vines growing in Europe are planted on root stock.
For my study I will present three different Cabernet Sauvignons; one planted on traditional root stock, one that is self-rooted, meaning no root stock, and one that is planted to a specific root stock called AxR1, which has it’s own checkered history. I hope you enjoy this look into this obscure, but interesting topic.Download Full Club Write-up