Cane pruning

There are many different shapes one can create when pruning a grape vine in winter in preparation for the next growing season. However, in all cases the objective is to leave behind an optimum number of buds or nodes on the last season’s wood that are evenly spaced over the whole growing frame of the vine. What is optimal for your vine can be learned only from experience with it over a number of seasons.

The two most common methods of winter pruning of vines trained on vertical trellis, as in most vineyards, are spur and cane pruning. Spur pruning is the easier method to master. I have described and illustrated it in my posting on 1 January 2010 on this blog (called “Winter pruning of vines from infancy to their fourth year”) . Here I describe cane pruning and discuss its advantages. But first the method itself.

Once the vine has reached a productive age of 3 or 4 years it will have a trunk and one or two horizontal arms coming off the trunk and tied to what’s called the fruiting wire. Those arms are called cordons if they are left there from season to season. The canes growing off the cordon’s buds are spur pruned each winter to two or three of their buds as described in my 1 January 2010 posting.

The unpruned vine in winter

The vine is pruned to two well positioned canes

If, on the other hand, one wishes to replace the horizontal arms altogether every season, one needs to practice cane pruning. This requires leaving two of the best positioned canes near the crown of the trunk, pruning away everything else from last year’s growth, and then bending down and tying the two reserved canes to the fruiting wire. These buds on these canes will send up fruiting shoots in the following growing season, which will be tied into the trellis wires above the fruiting wire. And in the winter that follows the vine will be cane pruned again to give it a fresh pair of canes to serve as its arms.

The canes are tied down to the fruiting wire

Take care not to snap a cane when bending it down to tie to the wire. The longer the cane the easier it will be to bend. However, the flexibility of the cane will depend on the air temperature, whether the sap is flowing through it, its thickness and the angle at which it grows away from the previous year’s arm. If the cane does not bend at will, it is imperative to leave it alone, unbent and untied. When spring comes, the vine warms and starts to grow again the sheer weight of the new shoots growing away from the cane will slowly bend it down. Then you can tie it down safely to the fruiting wire.

The advantages of cane pruning over spur pruning? Some varieties of grape  vine consistently produce more bunches of grapes if cane pruned than if they are spur pruned. Arching of the cane when tying it down will in itself greatly stimulate the productivity of the buds located along the region of maximum arch. And the annual renewal of the horizontal arms by cane pruning means the vine carries less weight and is less prone to diseases of the wood. Even the periodic renewal of cordons that are annually spur pruned with new canes – say every three or four years - helps to rebalance and reshape the growing frame.

Cane pruning requires more skill than spur pruning. But it  can be learned with less hazard to the vine if you do a practice run, as follows. Take a handful of brightly coloured clothes pegs. After careful observation of your unpruned vine attach your pegs to the points along the vine where you intend to prune it. Then stand back again and double check to see that you will attain the basic objectives  of retaining the ripest, healthiest and best positioned canes with an adequate number of growing buds on them spread evenly along the available length of the fruiting wire once you tie them down.  Then cut away all the unwanted wood from the previous season, watching out for your fingers and the wires. Finally, tie down your chosen canes and only then cut them back to the desired length.