There are two types of grape pruning - cane pruningand spur pruning. Mature plants should be prunedyearly to remove all growth except new 1-year-old fruiting canes and renewal spurs (a cane pruned back to one to five buds). To cane prune, select two to four new fruiting canes per vine. https://extension.oregonstate.edu/news/dont-be-timid-when-pruning-grapes