I planted a vine a year ago and it's doing fine and growing well.
I am training it to go over the fence to reach the pergola on the other side.
How should I prune it for next year's growth and when?
Gardening & Landscaping Stack Exchange is a question and answer site for gardeners and landscapers. It only takes a minute to sign up.Sign up to join this community
Yes, you should prune the vine.
In early spring, before the buds start to growth is a good moment to prune. The shot should be woody.
I would prune at 80% of the fence, and probably kill the lower buds, so that you will have 4 or 5 branches on the top. They will growth faster.and form your pergola, but I think they will not produce (many) grapes. You should wait an other year.
Remember to good fertilize the vine, on first years: you need it to expand a lot and get the form. Then you can reduced it, for more grapes (and to reduce the pruning).
Assuming you just want a single stem to grow over the fence to reach the pergola. This winter, after leaf fall, cut that short cane at the base back to the main stem. Do the same for any other shoots on the main stem. Next year, allow a single strong shoot to grow from the top of the stem and train this to the pergola as desired. Stop all other growth along the stem at about four leaves. Remember that grapes will form on the current years growth, so you'll need a permanent woody framework tied on to the pergola. Each winter remove the fruited canes back to the permanent framework.