Phylloxera had almost destroyed European viticulture, but in some parts of Italy it is still possible to find these spectacular vines, these “ungrafted” vines. We talk about it with Alberto Palliotti, professor at the University of Perugia – Department of Agricultural, Food and Environmental Sciences.
Professor, what is meant by the term “free foot”?
The ungrafted vines are vines that do not have rootstock, therefore it is Vitis Vinifera both for the aerial part and for the root part. They are a rarity, because Phylloxera Vastatrix, an aphid from the United States, had almost practically destroyed European viticulture in the late 1800s, destroying the root system of Vitis Vinifera. We were forced to use the grafting technique developed at the end of the 19th century. It is a real graft, therefore it is a biological control system, the first to be put in place, and after 140 – 150 years we are still forced to use it by law because otherwise this phylloxera which is now very present throughout Europe it can still destroy the European Vitis Vinifera. There are very few left around so this is a bit of the reason why we are forced by law to use American rootstock in new plants, since it is very resistant unlike the European one.
So by “ungrafted vine” we mean a graft-free plant?
Yes exactly, the propagation of the vine until the advent of phylloxera was by “cutting”: a shoot was placed in ideal conditions to form a root system and therefore there was no need for this grafting. Following this disease, the system has allowed to induce biological resistance, however, since there is the graft between the European aerial part and the American root system, it is a cut, a real wound, after the graft it is necessary that there is the reconnection of the pots and therefore this explains why grafted vines have a limited duration compared to free foot plants. These are over a hundred years old, while the grafted plant already loses its functionality after 20-25-30 years, so much so that the vineyards need to be explanted and replanted.
What are the areas in Italy where it is still possible to see these centuries-old plants?
In reality, the aphid does not live everywhere. There are some situations in which it is unable to close its biological cycle and therefore stops, for example in very sandy soils, in volcanic ones or where perhaps at one time of the year there is water stagnation, therefore asphyxiation. In Italy almost everywhere we find small areas where it is possible to find plants over a hundred years old free of foot, for example on Etna or in the Vesuvius area, Campi Flegrei, but also in Umbria in the area of Orvieto, which has an alluvial area where free plants are found, but also in other areas for example in the Po del Ferrarese or in the Sulcis area or even in the high mountains. In the Aosta Valley, after 1000 meters of altitude, the phylloxera does not exist, it cannot close its cycle so all the plants become free of foot. But also in other countries, let’s not forget that 70% of Australian and New Zealand viticulture is done without rootstock, but also all the viticulture of Southern Argentina or Northern Patagonia is completely free of foot and therefore plants that can last for centuries.
What differences do we find in wine if the grapes are born and grow on a centenary vine or on a grafted vine?
We don’t have great scientific data to prove this, even if something has been done. However, I can think that a plant we say free of foot has a very expanded root system, strongly stabilized in that context and therefore it is certainly a plant that is able to resist environmental stresses in a much more marked way than the grafted cuttings we buy and the most of the vineyards we see around. This means that during the most stressful periods of the year, a deep root system is able to explore a very large volume of soil, the stresses are less invasive and therefore also the physiology or the primary and secondary metabolism do not find moments of block, so I think that the situation in the free foot plants is very regular over time, with an enhanced secondary metabolism and a more marked polymerization of simple flavonoids. So in the end these grapes on equal terms in my opinion can have softer tannins. This is what I feel like saying, even if I repeat we do not have much data to support this.
But today is it possible to plant ungrafted vines in the areas you have indicated or is it forbidden?
Definitely yes, in areas where it is certain that the aphid cannot close the cycle, it can be planted. Of course, there is still a risk, because situations and conditions can change, so the entrepreneur must take this into account. In all other parts, however, it is strictly forbidden, so producers must use rootstocks by force and by law. In these areas it can be done, but if conditions change the vineyard dies. We have also had examples in Umbria of commercial vineyards made by entrepreneurs who are also enlightened free-footed, but after 3-4 years it was all dead. So you have to be very very careful, it is a risk.
Professor, are these centuries-old plants still productive?
Wines that have the wording “from Vigneti Prefillossera” means prior to 1880 are wines from ultra-centuries-old vineyards, which are also sold with this wording and are of a decidedly important value, also because they are very few.
We talked about other areas of the world but also in Europe we have countries where …
Even in Europe, in France for example in the Gironde, there are sandy areas that can accommodate vines without rootstock, but also in Spain, almost everywhere. Let’s say that it is a very limited viticulture, however each territory has areas in which due to pedoclimatic conditions, altitude or volcanic soils very rich in potassium where the aphid lives badly and does not close the cycle so it stops there, it is unable to procreate and then the infections are automatically canceled. The territories that can host free foot plants are many, but they are all small areas. But I repeat we must be very careful because in nature everything evolves, so what today could be limiting, tomorrow, the day after tomorrow or not in 10 years.
In the case of Asprinio we find centenary vines married to poplars, did you happen to encounter some centenary vines in particular conditions instead?
Lately we have found several in the old woods of the central Apennines, now wild because humans have disappeared for over 40-50 years and in some locations above 900-1000 meters. For example, in Morro, above the Menotre Valley, above Foligno, there is a slice of wood with field maples, what in Umbria is called bianchella because it is a white wood, with a pecorino vine at the foot. We had the molecular analysis done and it is all ancestral pecorino, in the middle of a forest at over 1000 meters above sea level. There are no rootstocks there and they are plants that have never been treated by anyone. Now they are long-limbed trunks that reach up to 20-25 m and at the top there is a tuft of leaves with grapes. Each year these vines produce their grapes up there, on the top f