Spur-pruning refers to cutting back dormant grapevine canes, leaving "spurs" of two or three dormant buds. In cane pruning, the gardener removes all but two canes from each vine and positions each remaining pair of canes in opposite directions from the grapevine's "head" and ties them onto the fruiting wire. The gardener removes everything else except for several stubby, two-bud spurs occurring down on the head of each vine, which are left to produce renewal canes in two years.
Annual dormant grapevine pruning assures the production of healthy new canes each year, essential because only shoots growing from one-year-old canes produce grapes. Dormant pruning removes the previous year's canes as well as surplus one-year-old canes to freshen the vines, select the fruiting wood, maintain the training system and assure the quality of fruit production.
Dormant grapevine pruning occurs between fall leaf drop and spring bud break. It is best not to prune the vine while it still has late season leaves because of the possibility of sap bleeding and premature bud development, which are disastrous to the next season's fruit-producing shoots if an early frost ensues. Because fall and early winter pruning increases the vines' susceptibility to freeze injury, especially in northern climates, it is prudent to postpone pruning until after the coldest winter temperatures have passed. Doing so allows for pruning adjustments to compensate for cold weather losses, and although vines bleed sap from pruning cuts made later in the winter, it does not harm them.