Pruning our fruiting plants seems a mysterious adventure which can deter us from pursuing and being successful with our fruiting plant maintenance each year. But don’t worry; there are some basic things to know which will help you in making good choices when getting your pruning done for the growing season. Here is a little primer on grape pruning which will help guide you.
The first thing to remember is that grapes are a vine and as such should be trellised onto a support. Additionally it is best to encourage a main trunk with radiating branches which become the main skeleton of the plant from which all new growth and fruit emerges each year anew. This skeleton framework remains intact and does not get pruned except in cases of damage or death of those limbs.
Grape clusters grow on new stems which sprout off the intact wood of the previous year. It is important to prune in late winter or early spring, before the new growth for this year has completely emerged and hardened off. This is generally done before sap starts to run but after the threat of a hard frost is past. Mid to late February is generally fine in the Pacific Northwest.
The coarser bark of old wood is easily recognizable; as the wood ages it forms gnarly branches with peeling bark. The new growth, by contrast, is smooth, slender and has tendrils which cling to anything in the vicinity, including slow moving passers-by. It also grows in leaps and bounds once the growing season is upon it.
To determine where to make your spring pruning cuts follow the growing tip back to the older wood it is emerging from. Then, come outward on the stem, leaving two buds and trim the outer part of the vine off completely. In some cases this can be quite a long shoot and makes one pause. Never fear though, this is the right thing to do and in fact if this is not done, by mid-summer your grape vine will be a mass of contorted stems so dense that even if grapes were able to develop you would have a heck of a time finding them come harvest time. The good news is that if your vine has leafed out, those young nubile leaves are fantastic for using to make dolmathes (dolmades), a delicious grape leaf wrapped finger food popular in Middle-Eastern countries and in my own kitchen!
Also remove all weak, thin shoots and leave only the strongest shoot to develop. The goal is to maintain that original skeleton framework with spaced vining shoots from which the fruit will develop and give each off-shoot enough space to develop properly and fruit well. You want fruit to develop close to the framework. You can be creative with how you allow the vines to grow, guiding them into trellises that have specific shapes, over arbors that create a shaded walkway or you can let them cascade over a patio arbor and provide a shaded sitting area for the summer.
Grapes are forgiving and appreciate this intensive spring pruning and will benefit from continual upkeep throughout the summer as they grow. Trim vines that emerge from intermediate areas to open the fruit to the sun as they develop. Leave at least 15 leaves per fruiting shoot to nourish the developing fruit.