Whilst vines can be seen to have evolved to grow well around the fringes of forest trees, on which they climb up unhindered, we now expect them to adapt to our needs in trellis systems, grasslands, grafting partners and frequent pruning.
Our management needs are designed to produce what we view as a crop most suitable for efficient wine making results. But where to start the planting?
As mentioned the vines adapt to differing soil types, and indeed we can further influence this by our choice in specific rootstocks. These have been selected for holding a range of merits, and indeed work continues by people seeking ever improved types.
This being relevant for some pest/disease issues, or perhaps future drier growing seasons.
There are groups of rootstock types, favoured by one social area of vine growers, say the growers in France, where others, in Italy or Germany might favour others.
We, as a nursery, are frequently involved in developing blocks of vines from differing rootstock choices, as field trials. Some of these selections were bred a long time ago, but are now being re-evaluated. Some are from more recent creations.
Whilst travelling, or working, in differing countries, I have noticed some of these different rootstock choices as well as the local favoured soil management methods.
For example whilst a rootstock choice such as 3309 C is favoured for its ability to set a moderate quantity of grapes, (easy to manage,) and noted for giving a more consistent and higher level of ripeness, this is also favoured for ‘agile calcaire’, the calcareous clay.
This in turn is frequently found to be a good soil type for under vine ploughing, and indeed alternative/or periodic row ploughing. Resulting in perhaps as much as 60% of the vineyard weed free, and the surface a broken clump type that inhibits capillary ‘lift’ of soil solution to the surface, (where it evaporates away.)
To use rootstocks known for specific attributes, and then manage the soil in a differing way, will give a different outcome. I have grown vines on 3309 C, on clay, and they have done well, however it is worth noting that clay holds onto the soil solution where other soils might be less inclined to do so.
Likewise my old hippy friends who favour vineyard management noted for a mass of diverse differing wild plants, frequently do so whilst using 5 BB K. These ‘wild weeds’ are aggressively competitive for the available soil solution, and this rootstock is strong enough to live with this.
There are rootstocks found closer to drier mediterranean regions, (gravel/small stone chip soils) giving deeper growing roots. Choices can also be influenced by the specific mineral attributes of a soil. For example for soils with a high level of calcium the rootstock Fercal has been developed. (This gives a nod of acknowledgement to the Ferrous-Calcium balance in a soil, where this is high calcium tolerant.) The other rootstock of recent note from France being Gravesac; used in washed out low lying gravel terraces to good effect. These are calcium deficient usually, with a correspondently higher influence from iron.
On the other hand… you could simply take cuttings from an existing vineyard, and use these to start a new block. I did this with Pinot Noir in New Zealand, and they showed themselves to be drought tolerant and gave as good, or better, grapes as compared to 3309 C, and certainly better than 101-14 (Millardet et Grasset,) (Couderc, Kober, Paulsen, Richter… the list goes on. A lot of people have done a lot of work in both creating rootstocks and evaluating them.)
Not a lot is written about rootstocks for cool climate winegrape production, but the Hungarian research grower in South Africa, Pongracz wrote a really interesting book about his experiences in trial work. Otherwise talk with your local colleagues, an experienced advisor or two, or phone your favoured nursery. So much for an introduction about the stuff under the ground, but there is plenty more to consider.
If you can forgive me, I will quickly outline my vineyard location choice in New Zealand. My thoughts were greatly influenced by some previous experience I had whilst working in France.
I did not want to manipulate the soils greatly, and I was not interested in using irrigation.
Whilst a lot of the New Zealand industry favoured wide herbicide strips, abundant irrigation, soil analysis/petiole analysis and applications like foliar ‘feeds’ and/or ‘bud builders’, they also had a low density of planting and high number of canes laid down with large numbers of buds. This approach is not for me.
For some of my time there I was working as an irrigation technician for this I monitored the ground water levels. This gave me an insight into how some people simply love spread sheets with a mass of numbers. Much the same as working with soil/petiole analysis…just a myriad of numbers and lumpy graphs. This upset or offended the artist in me so I walked away from it.
My vineyard lay on a clay ridge that ran south to north with rows that ran down the east side of the ridge, that stopped pretty much on the spring line that ran along the lower levels. I found an aerial photo that showed this line by a change of plant types in the grassland.
The ‘mist line’ that hung on this lower hillside in nights of still air, also lay very much at the same level as this spring line. The vines were planted at two metre by one metre spacing, fairly conventional stuff.
As the morning sun came up it quickly dried the dew on the grass that grew in the rows.
Then as it swung north, this being the southern hemisphere, the canopy gave some shadow onto this soil. When in the mid afternoon it was sufficiently over in the west, the late and very warm rays of sunshine came closer to running parallel to the hillside angle, and thus did not bake the soil overly hard.
As the angle of the hill was quite steep, then in periods of heavy rain much of it simply ran off it. Over all the soil got neither very wet, or became very dry.
The success of the decision to plant here, became noticeable by the significant increase in worm casts as the worm population grew at an extraordinary rate.
No irrigation, no fertilisers, minimal fungicides as it was above a mist line and was warm with gentle air movement shifting around the larger valley and coast line and as thin a line of herbicide as could be got away with, under the vines.
Situated about 15 to 20 metres above sea level with a long growing season. On the occasional day of more robust winds, these occurred blowing in from the south and west; the sheltered angle from over the ridge line. A good place to live, if for nothing else.
Actually the soils could be described as being fairly rubbish, but this needs a qualifier.
The ‘kitchen garden’ was a struggle, where with only some fairly massive efforts in making compost type additions did anything much grow there.
However trees did do well and it was in a region noted for fruit trees. In one of my very occasional dabbles into soil or petiole analysis, I came up with a couple of significant concerns.
Some people might say the soil was ‘sour’, and certainly the acid level increased the deeper I looked, (e.g. down in the root zone.) I put on a goodly dusting of lime every couple of years, and for a dozen years. This certainly boosted white clover growth, and probably favoured the worms as well. However I never got to know just how effective this really was, as lime travels downwards through clay soils at a very slow rate. Heavy applications coupled to deep ripping and ploughing, prior to planting could well have changed that, this though was not my style of approach.
Later petiole analysis indicated a presence of iron in the vines at early grape ripening time, at a level that could only be described as stratospheric. (Four times the supposed accepted maximum and right off the scale of any graph.)
I had a feeling that this was going to be the way, and this was prior to planting and thus my vine choices. White varieties err towards a noticeable mineral character in fruit flavour, (where calcium richer soils give a more opulent, wholesome richness to grapes.)
Here in Germany it is interesting to note that in some hillside vineyard regions, a horizontal track, or headland, can be found on a strata of rock change. One side might be a noticeable iron rich sandstone, where the other side is a more calcium influenced soil.
Occasionally both above and below this strata change there are vineyards of Riesling.
Companies with both of these vineyards may well put out two, and differing, wines.
Naturally these vineyards have very similar climatic conditions in any given year, they being about 100 metres from centre to centre. (Perhaps the soils differ a little in soil solution holding abilities,)
Go to a good tasting and find these two wines…same wine maker…same year etc, and they are not the same wine which is interesting.
My choice in Chardonnay, was the clone known as ‘Mendoza’. This has been considered as one of the most fruit abundant of clones, which suited me because I was looking to alleviate the effect of high iron in the soil. How this clone achieves this, is in part by its large number of very small berries, and thus high skin surface area per volume of grapes. It still carries a rather normal weight of overall kilo’s per vine. It is high in acid, but this moderates in the wine making, and ordinarily high acid and high fruit couple together well enough.
The rootstock for this was Schwarzmann, from a similar background as 3309 C and 101-14, but an earlier budburst type.
Given that Chardonnay is early anyway, this gave a budburst usually two weeks prior to adjacent Pinot Noir on 3309 C.
In one year we experienced a wickedly cold frost, (for this region, Nelson, in New Zealand) at about -3°C or possibly -4°C, measured in the valley floor where most people lived.
The Chardonnay shoots were about 3 inches long at this time, and whilst the cold air rolled down and out of the vineyard where it damaged other plants in the valley floor area, it did nothing to the hillside vines.
Red varieties with high iron produce very dark and rather tannic grapes.
When I write dark it can be seen that the resulting wines are dark to look at when the wine has a back ground, but strangely are lighter or clearer when looked through up into the light. Thus they are not ‘thick’ like an Aussie Shiraz but are more like a cool climate Cabernet Sauvignon from somewhere like Pécharmant, a small sub-appellation of Bergerac, grown on soils where only reds are allowed.
Enthusiastic hard working young Kiwi’s often fall into the trap of extracting too much from the grapes, as grown on these iron rich soils, where the resulting wine can be more akin to a black and earthy Corbières. Putting in enzymes and multiple plunging of the cap becomes excessive, and any delicacy of Pinot Noir can become lost.
As the vines were planted at 2m x 1m spacing, the pruning allowed for a conventional single Guyot approach, with the Pinot Noir this was a single 12 bud cane, but the differing rootstock in the Chardonnay appeared to favour a 10 bud cane.
The Chardonnay was much thicker wood and generally gave better individual fruit set.
The clusters were frighteningly tight, and where a local variant of a flower loving caterpillar set up home in the growing berries, they always got Botrytis.
However an introduced solitary wasp, Ancystrocerus a good caterpillar predator, was common in this fruit growing area, and it kept matters in some balance.
The Pinot Noir I initially thought might favour a yield of about 1.5 kg/vine, but on average it ran a little over this. The best year was both a 9 t/ha year and a crop that had an early, high level of ripeness. The lowest yield came in at 6 t/ha but was also early. In the 10 years that I took a commercial crop off this block, the difference between the earliest and the latest harvest, was but two weeks. For eight years out of 10 this was at 13.5% alc/vol, with the other two years at 13% alc/vol.
The TA was fairly stable, but for reasons that I never understood, was a little higher than the main cropping area in this region, about 15 miles further east. (Possibly soils as this area was mainly alluvial gravels or warmer nights with lower diurnal temperature range.)
The harvest was always hand picked, and I always suspected a small portion of second set grapes went in there as well, this is a frequent issue with the family of Pinot varieties.
There was a small block of Sauvignon on the hillside, spotted with some erroneous replants, (which I came to believe were Grenache Gris,) The resulting wine from this, when blended with a small amount of wine from Marlborough for its fruit forward characters, say 10% or 15%, gave a wonderful and elegant wine, in my, that is the grower’s viewpoint.
If the grower gets the homework right, and the vineyard is tidily managed, then the grower can believe in the resulting wine, it does not have to be a ‘copy book’ reflection of someone else’s previous production. Go walk your own path.
Site selection, soil types, topography, rootstocks, varieties and clones to name a few, there is much to be considered. However learn to avoid a few ’cause and effect’ trip hazards and there are many differing means to create wines of note, and wherever you choose to put roots down it’s all in the soil…
