HEARD IT THROUGH THE GRAPEVINE
Cane pruning (Guyot) is where the cordons/arms are cut off minus a single cane (or two) either side of the crown. These canes will have about 6 to 10 buds and will be trained along the fruiting wire, these buds will produce shoots that will be next season's production. Come the next winter, that cane will be removed and replaced by a new one year old cane and the cycle continues. This technique limits the lignified growth (wood that becomes 'woody') to just the trunk and seems to be a better technique for older vines (that incur wood/insect diseases), or those in cooler/wet climates (that incur winter damage), or where cordons are damaged and beyond repair (from machinery).
Spur pruning (Cordon) is more common in warmer climates growing regions like Australia and in "middle aged" vines. The Cordon is a horizontal extension of the truck and remains in a permanent position year after year, growing thicker and thicker each year. While the vine is in dormancy, we prune the canes from last years spurs to be next season's production. The spur positions (about a hand width apart) support one cane that is pruned short and in our vineyard to two buds. These two buds will grown into canes and each bud will bear two bunches of fruit. We also grow a 'reserve' cordon just below the crown in case we need to replace one of the main cordon arms.
Then of course there is the really technical reasons:
Why cane prune? Because spur pruning is too difficult. Why spur prune? Because cane pruning is too difficult.
August/September 2017 Newsletter