Today, Stolpman Vineyards stands at 41% own-rooted, with over 100,000 vines on their own European Vinifera roots. While this exposes us to the risk of phylloxera, we believe that Ballard Canyon’s arid climate, combined with our practice of withholding irrigation for six months every year, greatly reduces the likelihood that the bug could live and thrive in our vineyard. The root louse is much more destructive in wetter, more humid climates, where it can reach a winged stage of life and travel from vine to vine.
Own Rooted Vines: The Benefit
Own-rooted vines behave maturely years earlier than grafted vines. They require far less water to get established and can live without irrigation years before grafted vines can. The vines are able to regulate themselves, rather than rely on American rootstock for feeding. We don’t need to worry about the health of the graft union, and, we don’t need to worry about contaminated or weak rootstock material coming from nurseries.
For wine quality, not only do we reap the benefits of concentration and character from earlier dry-farming, but we feel we get more fruit purity from own-rooted vines.
The Simple, Natural, Art of Own-Rooting
When we own-root a new vine, we simply take a cutting, a dormant shoot that would normally be discarded after pruning, and place it in the ground. Ruben requires at least two buds placed under ground – these will naturally grow roots – and three buds remain above ground – to grow leaves and eventually grapes. Note that each cutting must be at least five buds long to successfully own-root with consistent success.
Not only do we need back-up buds for both roots and leaves, we also need a long enough stick to securely anchor the cutting into the ground, holding it upright to grow.
When we graft into a rootstock vine, we simply dig a small hole into the flesh of the trunk, place a small cutting into the flesh, tape it in, and allow for the vines to naturally bond. The shorter the cutting the better so as to stay in place, only one or two buds will do the trick.
An Obvious Benefit
Because we have an extremely limited number of cuttings for each new clone in the vineyard, we must look at how to most efficiently propagate these vines. When the new clones will be pruned for the first time we might be able to get 4 lengths of five buds each from a year old vine. But if we graft onto an existing rootstock vine, we only need a tiny segment with one bud, and we can multiply each existing one-year old vine into 20 new vines rather than four.
Spoiled by the Hearty Rhones
In 2013 we began playing around with light-bodied, fresh wines in collaboration with winemaker Rajat Parr. These varietals are destined for our Combe label.
Following the initial success of one acre of grafted Trousseau, in 2015 we own-rooted an additional 1.3 acres of Trousseau and in 2016, we own-rooted an additional .5 acres of Gamay. The 2016 Gamay planting coincided with 11 additional acres of own-rooted Mourvedre, Syrah, and Grenache plantings. In 2017, we will harvest a conservative crop of all three of the heartier varietals while the Gamay will not produce any fruit. Trousseau, with a year’s head start, will produce a tiny crop, less than the per-acre yield of the younger Rhone vines. Many of the Trousseau and Gamay vines are still thin and stunted, while a significant minority failed to grow at all, and have been replanted.
The lesson seems obvious: the delicate, lighter varietals have a more difficult time establishing themselves in the extremes of Ballard Canyon. Along with the 4X acceleration in propagating via one-bud long grafting sticks, we will see a further increase in success-rate by establishing strong root-stock vines this year, and then grafting on the more delicate varietals next year.
Of course, nothing can be quite so simple when it comes to farming. The 2015 Own-rooted Trousseau has been especially hard-hit by gophers (the rodents can easily kill young vines by eating roots), and after Rajat Parr’s recent research trip to Europe, he now has concluded that in France, Gamay is only planted on acidic soils. With the highly alkaline, active Limestone at Stolpman, we might find that Gamay doesn’t like it here, period, whether on rootstock or own-rooted.
Plan Going Forward
We now have 2,000 rootstock vines planted in the ground. They will grow roots this year and we will graft one-bud lengths of our newly acquired, delicate European varietals onto them next year. We will also keep a couple hundred rootstock vines growing so as to have a rootstock nursery. By propagating our own rootstock, and our own vinifera, we will further cut down on the exposure to outside viruses.