Training methods and pruning
When to prune.
The main pruning is done during the dormant season - typically late November through to early March. If you have only a few vines I recommend a warm spell in February.
A number of training methods have been described in the literature and on my visits to vineyards, I frequently seem to see ones that are not!
It is important to understand how vines develop. New shoots grow from a bud formed in each leaf axil. Strictly these should be called nodes because each node contains three buds from which future growth may take place. Growth tends to be strongest from the topmost node which produces chemicals to suppress growth from lower nodes – this is why trees have ‘leaders’ or ‘leading shoots’.
The aim of pruning is to leave sufficient nodes to provide enough shoots to bear the desired crop. The first decision is what type of pruning to use.
There are many methods documented, between them, Rombough, Rowe and Smart describe most of the important ones (see books).
As vines are pretty tolerant, you can also experiment to develop a method to suit yourself.
Whatever method of training is adopted you will probably need a suitable trellis to support the growth. I have used the same brand of plastic ‘wire’, a proprietary tensioner and professional clips for many years. See trellis illustrations.
The choice is between rod replacement and spur pruning. The difference between the two is not unlike the difference between the pruning of summer and autumn raspberries. In the former (a parallel for rod replacement), selected canes of the current year’s wood are left to fruit in the following year; in the latter the plant is cut to the ground and the fruit grows on entirely new growth from ground level (which is comparable to spur pruning, except the vine is NOT pruned back to the ground but to a suitable node).
Rod replacement pruning
In the rod replacement method, rods (i.e. canes or shoots) are selected and generally bent into position and tied. Bending rods may cause the bark to split and choosing suitable rods can be a bit of challenge to the beginner. Patricia Atkinson (see : Books : The Ripening Sun) eloquently describes her first reactions to hearing the bark split!
One problem with this method is that the nodes may not break uniformly along the length of the rod (e.g. if the topmost node is successful in suppressing the others). Another is that some nodes may face up and some down which varies the direction of the initial growth thereby adding difficulty to the management of the new shoots.
The Guyot method of training
The most common rod replacement method is called the Guyot method and is described in most text books. See trellis arrangements - last illustration
A spur is simply one or more nodes left after pruning - usually on last year’s wood. By careful selection, the vine structure can be trained into the required shape and shoot development can be managed more precisely than with rod replacement. The most common method is called ‘vertical shoot positioning’ in which a permanent, horizontal cordon is grown at a convenient height above ground (typically 600mm or 2 feet ) and vertical shoots are allowed to develop at selected positions (typically every 100 to 150mm or 4 to 6 inches). The vertical shoots or even the entire horizontal cordon may be replaced from time to time as required.
Going back to the raspberry analogy, it is easier and quicker to prune autumn fruiting raspberries as it requires no thought – just cut down the lot! Similarly, once the vertical shoots have been established, pruning consists mainly of cutting back to the spur or a suitable replacement spur.
Some vines are said to respond better to one or other method and Seyval Blanc is said to respond well to spur pruning – something I can confirm from personal experience.
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