In many cases orginial source is obscure or in doubt. Dr. Austin Goheen, Univ. Burgundy via Oregon State Univ. Burgundy via Oregon State Univ. Burgundy via Oregon State Univ.
Vines are head pruned and cane pruned.
Several methods are used to minimize the impact of winter cold injury on performance. These include multiple trunks and double pruning wherein extra canes are retained during dormant pruning and those not required for fruiting are removed following bud break. The goal is for each vine to have 27 shoots per vine. Vertical canopies are ensured by the use of moveable catch wires. Vines are topped when shoot growth threatens to droop and shade the lower canopy.