The first year I was to prune back my vines, my German Shepherd 'pruned' one of my vines for me. He simply chewed it down to about 5 inches from the ground. The next year my 'pruned' vine produced a most wonderful crop of grapes; however, they rarely make it into the house. They're just too good to wait to eat them inside. Each year after correct pruning the grapes produce a prodigious amount of grapes for me. This year I am hoping that I get to make juice and/or grape conserve.