Ungrafted v. Grafted Vines

Until recently, I hadn’t given much thought to the impact of grafted vines on the general quality of wine made after phylloxera. I contented myself with reading here and there that the use of American rootstocks had not affected the flavor profile of the grapes. Not to mention that, since there is nothing that we, as consumers, can do about it, and very little that the overwhelming majority of producers can do about it, I would have preferred not to know.

A few weeks ago, however, I read a fascinating interview with Portugal’s Luis Pato in which he talks about the wine he has been making since 1995 at his Quinta do Ribeirinho in the region of Bairrada using the Baga grape planted on sandy soil (which the Phylloxera bug hates) using ungrafted vines (pé franco, in Portuguese, franc de pied, in French). Pato said that bunches and grapes from ungrafted vines are both much smaller, leading to a higher skin to flesh ratio and wine that is more tannic and concentrated. I have yet to find/try this wine, but my curiosity is definitely piqued. Recently I saw a note from Dale about Catherine and Pierre Breton’s ungrafted cabernet franc, so I picked up a bottle at Chambers earlier in the month and hope to try it soon. Anyway, going back to Luis Pato, a picture is worth a thousand words, so here is one (I hope this works), from his website, showing a grafted bunch (left) next to an ungrafted bunch (right). I wrote to Mr. Pato asking if they were the same age, and he kindly wrote back saying that the ungrafted vine was 20 yrs old and the grafted 16 yrs old, making the size differential due to age negligible. Pretty interesting stuff, I think.

Pe Franco v Pe Enxertado.jpg

you refer to 'ungrafted rootstocks'; but i'm not sure this is the right wording. rootSTOCKS are things that you graft things onto. ungrafted vines are 'own rooted' - they do not use rootstocks. OR is he using pure vinifera rootstocks - just not the ones from the variety he is growing?

you refer to 'ungrafted rootstocks'; but i'm not sure this is the right wording. rootSTOCKS are things that you graft things onto. ungrafted vines are 'own rooted' - they do not use rootstocks. OR is he using pure vinifera rootstocks - just not the ones from the variety he is growing?

Thanks, will go back and revise!

Hopefully others more knowledgeable will chime in but I don't think it's surprising that grafted and ungrafted vines behave differently. It's not so much that grafted vines will always produce more heavily than those on their own roots, it's that different grapes have different degrees of vigor and that applies to both rootstock and vine. Any variety behaves differently depending on what rootstock you graft it onto. Accordingly, rootstocks for grafted vines are chosen very carefully depending on the variety to be grafted onto it as well as local climate and soils. If the same variety behaves differently on different rootstocks, of course it will behave differently on its own roots. It appears in this case the vine is much more vigorous (or at least produces more fruit) on the rootstock that was chosen for the grafted version than it is on its own roots. The opposite might be true with different variety and rootstock. I don't think you can generalize from this, that grafting onto non-vinifera rootstock necessarily changes the "flavor profile" of grapes. It might or might not but this one example doesn't tell us much.

Any variety behaves differently depending on what rootstock you graft it onto. Accordingly, rootstocks for grafted vines are chosen very carefully depending on the variety to be grafted onto it as well as local climate and soils.

Exactly. Rootstock is very important. The scion variety and the terroir are much discussed, but the bit inbetween is sadly neglected. Mainly because is it not sexy enough for marketing purposes I suspect.

Grafting of vines is itself an entire subject. Usually you never hear about it until things such as the 1990s Sonoma AxR disaster happen. Rootstock varieties vary greatly in their soil preferences, disease resistance, willingness to accept vinifera grafts, and just about every other important dimension you can think of.

On the other side, according to Jancis Robinsion's book there are several vinifera varieties that were widely planted before phylloxera but are not cultivated much now because they don't take rootstock grafts very well.

-Paul W.

One thing that struck me as odd: why would anyone want to increase the skin to pulp ratio in Baga? It is a somewhat hard/tannic grape as grown on the grafted vines (since I have not had Pato's ungrafted cuvee). Pato is a big advocate of Baga as a fine wine grape, and I generally like what they do, so he must have his reasons. Earlier this week we had their Baga espumoso (sparkler), which is quite full bodied, well colored and different.

Any idea what rootstock the grafted plants are on? Also is it known if all other conditions are same, i.e. vine density, trellising, soil composition, etc.? While rootstock can impact berry size, bunch size, vigor etc. so can other factors such that unless all other conditions are the same one can not assume that rootstock alone accounts for the difference in the picture.

Joe Dressner has also observed that several Loire valley vignerons have done side-by-side comparisons of grafted and ungrafted Cab Franc. He also reports that the grafted vines were substantially more vigorous, though he didn't provide photographic evidence such as Pato's. His explanation was that rootstock was typically chosen for its vigor, so tends to provide for more vigor than native rootstock. (Or could it be that v. labrusca is inherently more vigorous than v. vinifera?)

Mark Lipton

...Or could it be that v. labrusca is inherently more vigorous than v. vinifera?
Mark Lipton

I don't think v. labrusca is used in rootstocks. I think most are vinevera crosses with Vitis rupestris, Muscadinia rotundifolia and/or V. riparia. I recall a story about Dr. Konstantin Frank selecting wild grapes (V. riparia) growing in a field (1950s) and he successfully used it as a rootstock for vinefera.

There was a very good discussion about rootstocks in the Wine Business Monthly a few months ago. One of the many interesting points raised was that one of the reasons for the higher alcohol in CA wines recently might be the prevalent rootstock.

I have a Falanghina and Piedirosso from near Naples, in an appellation so sandy that the vines don't need to be grafted. The grapes for both red and white are picked in early October in a hot climate and the wines come in at about 12%...