Every year, round about December, I attach my hydraulically operated trimmer machine to my red tractor and buzz around the vineyard giving the vines a bit of a trim. This is called tipping and topping in viticultural terms.
Here are the before and after pics in one of the Gruner blocks.
The ‘after’ pic does look a lot neater – but this is not the main reason for doing this tipping and topping procedure.
The main purpose is to remove the growing tips of the vines and once this apical growth has been clipped, you trigger a hormonal change in the physiology of the vine. (Hormones that are produced in the growing tips of the canes are abruptly removed.) One of the consequences of this sudden physiological change is the redirection of nutrients from the growing cane and its leaves to the developing fruit lower down on the cane. This is, of course, desirable at this point in time as the immature berries are developing and require much nutrient to fully evolve physically and also to develop a good supply of flavour precursors.
Other reasons for tipping and topping are that some of these growing canes can be very long and they are susceptible to being ripped around by the wind. A trimmed vine canopy has less wind resistance and is therefore more stable in severe weather. In addition, some of these canes can get very long during the growing season and will eventually flop over and shade the fruit zone. Not only is this undesirable for ripening purposes, but this ‘overhang’ can also restrict air movement and make the vine more susceptible to fungal infections.
For the chemically minded, there are reports that suggest that appropriate trimming will result in a better pH in the fruit at harvest time.
So – there are many good reasons for this summer activity. But the reason that I prefer most is that it does make the vineyard look pretty schmick!
I would like to take this opportunity to wish you all a wonderful festive break …. and a fantastic 2012 – for all of us!