How do I prune my grapes? What do I do about the bleeding when I cut them? These questions come up among novices and experienced gardeners alike — especially the first question.
Grapes are a rewarding backyard fruit and they are popular among gardeners. In fact, they have been popular items on the world’s menus for thousands of years because they are among the most versatile and adaptable of all small fruits and, obviously, because people love the very sweet flavor of these fruits. They do take a little longer to come into initial production than raspberries, strawberries and other small fruits, but with proper care they can remain productive for many, many years.
Some vineyards in Utah have plants that have been growing for more than 100 years and elsewhere in the world, some vines are much older.
Grape vines don’t take much space, and if you choose varieties adapted to our climate, you should get a good crop most years. Select American or American hybrid grapes. European varieties require too long a growing season to produce during our short summers and some are not hardy enough to withstand winter cold. The time for pruning grapes to get optimum production is from now until they break dormancy. You will remove more from a well-pruned grapevine than any other plant in your yard. Pruning should remove about 90 percent of a grape vine each year but not in a random manner.
If you visit vineyards in other areas of the country, you will see grapes pruned using a variety of different methods. Each system is a good one but the best one to use depends on location and grape variety. Not all pruning systems work well in Tooele County.
In this area, experts recommend using a cane pruning system. Cane pruning is a method that grows a trunk or base cane, with selected canes growing out to the side. Support is essential for healthy growth. Build a sturdy trellis with two wires, one about 2 feet above the other to support a grape vine as it is first planted. You can also use a fence, lattice trellis or arbor as a support for grapes. Keep in mind that the plant will become heavy as it ages and produces abundant crops. Make sure your support is strong enough.
The cane pruning system requires the grower to establish a trunk that reaches to the top of the arbor or trellis. Once established, it should not be cut or damaged. It provides support for the rest of the plant. Fruit develops on wood that grew the previous year only. It does not develop on wood that is more than two years old or less than one year old. You prune to develop fruiting canes that will fruit this year and also canes that will develop this year but will not fruit until next year. This involves leaving fruiting canes and renewal spurs.
A healthy plant will support about 60 buds on fruiting canes. As the plant grows more mature, it will likely support more canes. This allows the plant to support fruit production as well as to establish more wood and foliage for the next year. Select four healthy, sturdy canes to become your fruiting canes. Fighting your way through the tangle of vines to select canes for this purpose can be a challenge, but it is important to do it. The ideal cane is slightly larger in diameter than a pencil. Larger canes produce lots of leaves and vegetative growth rather than fruit, and smaller ones are too weak to support the grapes. Along with fruiting canes, select four more canes for renewal spurs. Renewal spurs are simply long canes that are cut back to two or three buds. Once you have selected these canes, remove everything else. Cut back the four fruiting canes you have selected and cut them 10 or 15 buds each.
Cut the renewal canes back to two or three buds. These buds will be allowed to grow through the summer to provide wood for next year’s crop.
Many people make the mistake in planting new plants and leaving them for a year or two to “get established.” Start training them the day you plant them and continue the process each year after.
Plant grapes as soon as the soil dries out enough to work. Cut the transplant back to two buds. Plant it in a hole at the same level it would have been growing before it was dug for transplant. As the buds grow, take the longest and most vigorous shoot and train it to an upright position. This will become the main trunk. For the first year, that trunk is the prime concern. Don’t worry about side branches.
During the second year, branches begin to grow. They will not produce grapes for another year. Use the second year to train the branches to the trellis. For a four cane system, choose canes at about 30 inches off the ground, one in each direction. Two more canes will be trained 30 inches higher. These canes will produce fruit the third summer. Create renewal spurs near the base of the fruiting canes to allow the plant to grow long, vigorous vines for the next year. These vines are not trellised, but allowed to grow somewhat haphazardly. The following spring, remove fruit-bearing canes from the year before cutting near the trunk. They will not be of any value in fruit production that year. Sort through the remainder of the vine, and choose the most vigorous cane from each of the renewal spurs that were cut last year. Attach those to the trellis supports after cutting them back to 10 or 15 buds. Choose one more cane from each spur for another renewal spur for the next year. Repeat the process each year. Remove old fruiting wood and create fruiting canes for that year’s crop and renewal spurs for the next year.
The sap that drips from the cut ends of the plant is not finite like blood. Sometimes gardeners become alarmed when their pruning cuts drip sap for long periods of time. This weeping is simply the plant moving fluids from the ground through the stems and out the ends. It will continue until the plant breaks dormancy. It is not harmful, so don’t do anything about it. If it bothers you, don’t look.
Pruning grapes can seem complicated, but it is well worth the effort for the sweet, juicy flavors you can enjoy at the end of the season.