According to legend, it was a donkey that discovered grapevine-pruning: Somewhere in Palestine, the creature nibbled away at a vine, and to the dismay of villagers, this vine produced exceptionally large fruit! Realizing the donkey was on to something... the pruning began.
As quaint as pruning's inception may be, every amateur-vintner does need to consider present day developments and apply relevant pruning methods. Newly planted vines are almost always grafted, and usually onto hardy rootstocks like 5 BB and 125 AA. In the past, ungrafted house vines were 'boosted' by placing them in huge planting pits filled with manure and other slurry fertilizers. Today's grape varieties are often too vigorous for the private garden and need to be handled differently.
The old types of viticulture produced fruit almost entirely with cane pruning (long pruning), a pruning form which tends to exhaust the vine. With the resulting lack of vigour, the stem framework had to be gradually developed over three years, starting with spur pruning, then switching to rod pruning, and ending with cane pruning... meaning the vine gave fruit only every 3 years. All branches on the vine had to undergo this slow cycle ~ essentially an 'alternate pruning' method and certainly not easier than today's techniques.
Each wine-growing region had its very own way of training and pruning grapevines; standardized methods (that is, the most effective viticulture techniques) did not really appear until around 1930.
The vine's main pruning takes place in winter. Old books give the impression that the vine gives fruit only when they are continuously snipped and pinched, also in summer. They promote the painstaking removal, or at least the shortening, of any axillary shoots growing from the leaf axils. Maybe this was necessary for the historic, non fungus-resistant varieties; however, anyone who insists on sticking with these treatment methods and not losing track of everything, risks ending up on a psychiatrist's couch and missing out on the harvest! It is now recognised that these axillary shoots are actually of nutritional benefit to the vine; alternatively, new varieties are bred with fewer axillary shoots, which solves this problem.
The topic of grapevine pruning does not come without debate, and even quite some emotion! What proves successful for certain varieties in one region, may be impractical or rejected as nonsense elsewhere. Fortunately, the grapevine is a flexible plant that can be easily manipulated; it willingly sprouts even after the most radical pruning. The biggest and most common mistake in vine pruning is that people do not prune enough. Anyone who observes his/her vine closely over the years will quickly discover its needs and preferences, and which pruning technique it responds to best.