Andrew Naylor, Pernod Ricard, NZ

Name: Andrew Naylor

Vine balance the key to success

Grapegrower & Winemaker: Is Sauvignon Blanc more or less suited to particular styles of pruning or trellising?

Andrew Naylor: Generally, cane pruning suits Sauvignon Blanc. Its basal buds are not very fruitful, and past experiences with spur pruning have been unsuccessful.Either two, three or four cane VSP pruning will work depending on the site, and we employ a range of those. Sylvos pruning can be used but the number of buds and canopy have to be managed for higher price point wines. Sylvos has some drawbacks - it can produce a heavy crop; in vigorous sites fruit shading results from shoots growing back into the canopy; the canes don't flex well and many break in the process of bending through 180 degrees to be tied down. Scott Henry trellising can work well for some sites but a degree of vigour is required to sustain it. Sauvignon Blanc shoots break out very easily though and a large number of them may be lost to Scott Henry when rolling the lower canopy.

G&W: Spur or Cane pruning? If cane, preferable cane length and number of canes.

AN: Definitely cane pruning. We have most of our Sauvignon Blanc plants 1.8 metres apart and aim to have a gap of about 10 centimetres between cane ends once wrapped. That's about 12-15 buds per cane. The number of canes (buds) needs to reflect the site and vine vigour. Wines worthy of a higher price point are going to come from balanced healthy vines. We have two, three and generally four cane vines all providing great fruit for their intended products.

G&W: What are the ideal bud numbers aimed for?

AN: Again it's going to be about balance. On our stony, low-vigour Conders Forest vineyard 36-40 buds per vine works well. Some of our Triple Bank fruit is coming from vines of similar bud number. At Brancott the bud number per vine for Estate quality fruit is around 50-55. The vines at the different sites are all in good balance within their site and so we are able to produce the wine quality we're after.

G&W: Is more canopy required?

AN: I believe the key is canopy health, avoid water stress, wind stress and nutritional problems. We trim to a shoot length of about 1.2-1.5m. Having vigorous growth from veraison to harvest is not going to work - shoot tips will compete with fruit for carbohydrates.

G&W: Do transpiration rates help dictate pruning methods?

AN: No, not for us here in NZ.

G&W: What is the soils, water and cropping effect on how or when pruning is carried out?

AN: With the numbers of vines that we have to prune we try to make a start in mid-May and aim to complete pruning and tying down by the end of August.
There is some distinction made based on soil type. On the stonier soils the cane lignifies earlier and the leaves senesce earlier than on heavier soils. So the vines on stony soils get pruned ahead of the heavier soils.

Apart from that it's a matter of ensuring that the right number of buds is retained. Where the crop load or water status of the vine has reduced the health of the canes we need to allow for that in the pruning process. As an example, if canes are thin and internode length is short we have to shorten the canes we keep or we'll have too many buds.

G&W: Is under-pruning more of a problem than over-pruning?

AN: I guess it depends how you define over- or under-pruning. If under-pruning involved leaving too many buds and a poor vine structure then that's a bigger problem for higher price point wines than over-pruning. The resultant crop level or canopy density may compromise the quality you're aiming for. If over-pruning means being too fussy about the tidiness of the vine head and structure then that's not as bad as ending up with out of balance vines. However, when over-pruning involves leaving too few buds then that's a real problem from a vine balance and income point of view.

G&W: Is it necessary to employ specialist pruners? Or does Sauvignon Blanc respond well to mechanical pruners?

AN: We only use mechanical pre-pruning for spur-pruned vines, and as we discussed earlie,r spur pruning of Sauvignon Blanc will not be fruitful. So, all of our Sauvignon Blanc is hand pruned. There are more skilled pruners becoming available with time but a lot of the labour force is transient. The local industry invests a lot of effort in ensuring that we promote ourselves to likely labour markets. We need pruning staff and each year we have to attract, train and retain them as well as we can.

G&W: Have recent weather variations forced changes in when and how pruning is carried out?

AN: No, not really. With the hectares that have to be covered and the availability of staff we have to be realistic that pruning will take 3 - 3½ months and we have minimal room to be fussy about exactly when blocks are pruned. Having said that, with the expansion of vineyard area there are a lot of young vines that need their first pruning. In a mild winter they retain their leaves a long time and the cane is slow to lignify so pruning is delayed.

After the November 2002 frosts Marlborough growers are probably more aware of frost risk. In areas prone to spring frosts pruning may be delayed to gain a delay in bud break. Labour availability has to be managed to achieve that though - not everyone can have their vineyard pruned in the last two weeks of the season.

G&W: What is the most crucial part of Sauvignon Blanc pruning that helps ensure quality when aiming for higher price point wines?

AN: Pruning for vine balance is the key. The effects of that are probably most evident in crop load. Crop level cannot be adjusted upwards later if too few buds are retained. Adjusting it downwards will incur a cost and the vine's performance may suffer in the meantime. The other downstream effects of poor pruning, shoot crowding around the head or poor fruit exposure can be altered throughout the season.

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