Your dormant vine may look like a dense tangle. After pruning, it'll look lean and orderly. "Pruning is a part of the control of the vine," said Paul. "You don't want the vine to take over."
On mature vines, the number of buds to keep depends on how much the pruned canes (branches) weigh. If you prune one pound (0.5 kilogram) of canes from a vigorously-growing varietal, you can leave 30 growing nodes -- budding points in joint-like rings along the canes -- on the vine. On slower-growing varietals, limit the vine to 20 nodes. For every additional pound (0.5 kilogram) of pruned canes, add 10 nodes.
Pruning is also important for disease control. By removing injured or infected plant parts, you encourage new growth and mitigate the spread of disease. Once growth begins, a properly pruned vine is open to sunshine and air flow. These healthy-growth essentials encourage vigor in the vine by facilitating photosynthesis and deterring many diseases and pests.