Single-curtain Cordon or Hudson River Umbrella System
The top wire in this system should be galvanized, crinkle wire, or brite basic number 8 wire that has the property of low stretchability. This is because once this system is established, the wire cannot be retightened. In training a vine to this system, select two strong canes or arms and place them bilaterally along the top wire. Arms from one vine should not overlap with arms from adjacent vines. For first-year pruning, leave several branches (spurs) that are five to seven buds long. These spurs should be spaced 6 to 12 inches apart. For each seven-bud spur, also leave a one-bud renewal spur. In selecting arms, be careful to avoid scored wood where canes cross over the top wire. The fruiting shoots will hang like a "curtain" in groups from the spurs that originate from the arms along the top wire. The arms should be wrapped loosely around the wire and tied at each end. One and one-half turns should be sufficient for each arm. Using a bottom wire is necessary only for young vines or for trunk position control.
Shoots should be separated carefully and placed vertically downward from the top wire for a distance of 18 to 24 inches. Positioning should be carried out as soon as the shoots have toughened, usually 2 to 3 weeks after peak bloom. Peak bloom is when 50 percent of the fused petals (calyptras) have fallen, exposing the rest of the flower parts. Extreme care must be exercised during shoot positioning since any shoot lost at this time can result in a poorly filled trellis.
During the second year and thereafter, leave at least five buds on each spur along the arms of the vine for fruiting purposes. The total number of buds should be adjusted in accordance with the capacity of the vine, as explained for other systems.