Pruning grapevines is an essential practice for maintaining the health, productivity, and shape of the vines. However, improper or excessive pruning can potentially harm or even kill grapevines. In this article, we’ll explore whether it’s possible to kill a grape vine by pruning and how to prune properly to avoid damage.
How Grapevines Respond to Pruning
Grapevines are remarkably resilient plants that can withstand quite a bit of pruning. The vines respond to pruning by redirecting their energy into fewer buds which results in vigorous new growth and better fruit quality.
Proper pruning removes excessive growth allowing the plant to reinvigorate itself the following season. Grapevines tend to be quite forgiving of pruning mistakes. Even severely pruned vines often regrow successfully after a season or two of recovery.
However, it is possible to overprune and cause significant harm. Removing too much growth can starve the vine, while improper pruning techniques can introduce diseases. Understanding grape vine biology and following proper pruning practices is key to avoiding damage.
When Pruning Can Kill Grapevines
While grapevines are adaptable, pruning can kill vines if done incorrectly or excessively. Here are some key mistakes to avoid:
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Excessive pruning: Removing too much growth deprives vines of nutrients and water uptake ability. Though vines resprout, fruit production lags for years.
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Pruning during active growth: Major pruning should occur when vines are dormant. Pruning during active growth stresses vines.
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Improper cut placement: Cutting too close to or too far from buds impedes proper healing and growth.
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Failing to remove dead material: Leaving diseased or dead wood spreads disease.
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Not matching pruning to variety: More productive varieties need less drastic pruning than low-yield varieties.
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Over-thinning: Excessive canopy thinning stresses vines by removing too much foliage.
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Frequent severe pruning: Repeated heavy pruning year after year prevents vines from restoring reserves.
Tips for Grapevine Pruning
Follow these tips to prune grapevines successfully:
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Timing: Prune mature vines during dormancy before sap flow begins in late winter or early spring.
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Appropriate intensity: Remove around 80% of current season’s growth, leaving 8-10 healthy buds per vine.
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Cut placement: Make cuts 1⁄4 inch above buds, angled away from the bud. Avoid leaving stubs.
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Tool sanitation: Disinfect tools between plants to prevent disease spread. Sterilize tools after pruning diseased vines.
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Remove dead material: Eliminate all dead or diseased wood, including mummified grapes, which harbor disease.
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Assess first: Evaluate vines for damage before pruning. Adjust strategy accordingly.
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Match to variety: Less productive varieties need lighter pruning than highly fertile varieties.
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Avoid over-thinning: Leave enough healthy foliage to support vine growth and fruit development.
Taming the monster: How to prune overgrown grapevines
Grapevines require annual pruning for health and productivity.
Photo 1. Grapes are excellent eaten fresh or made into jelly, juice or wine. Photo by Brent Crain, MSU Extension.
People have always loved grapes for their beautiful vines and the complex flavors of their fruit and wine (Photo 1). Even though grapes aren’t hard to grow, they do need some care once a year to make sure they produce high-quality fruit every year. Neglected vines can quickly outgrow their space and supports, leaving home gardeners struggling with how to proceed. Here are the steps to take to tame overgrown grapevines, restoring health and productivity through proper pruning.
Annual pruning is important for the health and productivity of grapevines. If you don’t prune grapevines, they may produce a lot of fruit, but the grapes will be smaller and less good. Some types of grapes may start to have an irregular pattern after a few years, with big crops one year and small crops the next. This different bearing is caused by the stress and demands of carrying heavy crops, and the plants may lose their strength and the quality of their fruit may suffer.
You can prune grapes at any time during the winter, but it’s best to wait until there is no longer a chance of spring freezes. Pruned vines break dormancy earlier, making them susceptible to freeze injury. There may be heavy winter damage to the vines and buds, so grapevines may be pruned after buds break. This makes it easy to choose from canes that are growing healthy new shoots. Although the vines will bleed sap after pruning, this sap loss is not harmful to the plant.
It is a good idea to check the canes and buds for winter damage before pruning. Damaged canes often appear darker and look less healthy. The buds, located at each swollen node, may be mushy or shriveled. If you cut open a healthy bud, the inside will look green. Buds that are dead or hurt will look brown, black, or very dull green. Cut open a few healthy buds from canes that will be cut back, and then look at the buds that you think were hurt by the cold. The difference should be readily apparent. You can tell if a cane is healthy by cutting it down and looking at the cross-section of the cane where the cut was made. The cross-section of a healthy cane will have a green circle of living tissue. If it is brown and dry, the cane is dead (Photo 2).
Photo 2. Cross sections of (left) healthy and (right) dead canes. Photos by Brent Crain, MSU Extension.
When grapevines are young, they are guided, or trained, into a variety of shapes. Sometimes the goal is for aesthetics, like covering an arbor, but most of the time it’s to make fruit production more efficient. When a grapevine is young, it can be trained in a number of different ways, which are called “training systems.” There are a lot of different systems because grape varieties have very different ways of growing and are very different in how well they respond to training. The trellising that the vines are growing on can help you figure out what kind of training system was first used to grow the vine. The most common way is to drive posts into the ground and string at least two wires between them. The wires should run parallel to the ground and about 2 5 feet and 5 feet above the ground. A more complex system has been used if there are extra wires on supports that branch off from the posts. In that case, refer to Growing Table Grapes for more information on training and pruning.
The four-arm Kniffin system (Photo 3) is the easiest way to train grapes if the vine is held up by two parallel wires strung between posts. This system works best for Concord or lubrusca grapes and lets a lot of air and light in during the hot summer months. With this system, a perennial trunk—identifiable by its shaggy bark—is trained up to the top wire. In badly neglected vines, there may be many old, thick arms growing sideways along the wires. You want to keep the straight trunk but cut off the older arms because they aren’t as strong as the younger canes.
Photo 3. 4-Arm Kniffin Training System. Photo from
But before cutting anything, the first step is to decide what canes should be kept. Two canes should be chosen from the trunk near the top wire and placed along the top wire, one to the right and one to the left of the trunk. Mark these canes with flagging tape or twine. Do the same for the bottom wire. Select 1-year old canes of moderate vigor. Canes that are one year old will be smooth and a reddish brown color. Canes that are older will be grayer and have bark that is rougher. Look for canes that are about 0. 25 to 0. 375 inches in diameter. Smaller canes won’t grow very fast or produce much fruit, while bigger canes will grow too fast and not produce any good fruit.
Choose renewal spurs for the marked canes that have been chosen to train along the wires. This is the next step. For each marked cane, choose a moderately vigorous, 1-year-old cane originating from the trunk near the marked cane. Prune this newly-selected cane, leaving just two buds. Next year, at least one of these buds will turn into a new cane that can be trained along the wire. Renewing the lateral arms each year will ensure good production of high-quality fruit for years to come.
There should now be a total of four marked canes and four renewal spurs. Being very careful to not damage the four marked canes, prune off all of the remaining canes. This pruning will get rid of about 90% of the vine, but it’s necessary to keep the grapevine healthy and productive. After taking those canes off, the last step is to carefully place the marked canes along the wires. Place two along the top wire to the right and left of the trunk, and the same thing should be done for the bottom wire. Tie each cane loosely to the wire. Be careful not to break the cane.
After the pruning is done, the vine will have a vertical trunk, lateral arms that grow outward from the trunk along both horizontal wires, and a renewal spur near each lateral arm (Photo 3). If you do these things every spring, the grapevine will stay healthy and produce fruit for years to come! For more information, check out these other Michigan State University Extension resources for growing grapes.
Prune Grapes Vines This Way & Grow Big Sweet Grapes
FAQ
Can you prune a grape vine too much?
What is a mistake for pruning grapes?
Can you cut a grapevine back to the ground?
How far back can I cut grape vines?
How to prune grapes?
Let’s look at how to prune grapes. Grapes should be pruned during their dormancy, usually in late winter. When it comes to pruning grapes, the most common mistake people make is not pruning hard enough. Light pruning doesn’t promote adequate fruiting whereas heavy pruning provides the greatest quality of grapes.
Should you cut back a grape vine?
Practice balanced pruning to maintain the shape and health of each plant, and never prune two-year growth or older unless you’re trying to reshape or cut back a vine. If it’s your first time pruning your vines, you may be nervous about cutting them back too much. Don’t worry — grape vines are actually hardy plants.
How do you prune a grapevine?
When pruning grapes, you’ll want to cut off as much of the old wood as possible. This will encourage the growth of new wood, which is where the fruit is produced. While there are several ways you can trim a grapevine, all share the same basic steps for managing varieties that require winter protection.
Do grape vines need to be pruned?
Pruning not only helps shape the vines, but it also optimizes air flow, which is essential for their health. Grape vines produce fruit on one-year-old wood. The green shoots the vines produced each year will often turn brown by the end of the season, by which point they are considered one-year-old wood.
How do you cut a grape vine?
In severe cases, the grapevine will have to be cut at the trunk, almost all the way down to the ground, at the base of the vine. Shears aren’t able to cut anything of this sort of thickness, so one of these pruning saws will work best: You’ll want something pretty durable because this will be used to mark branches to be saved.
Should you prune grapevines after bud break?
Pruned vines break dormancy earlier, making them susceptible to freeze injury. If it has been a very cold winter and heavy winter damage to the vines and buds is likely, grapevines may be pruned after bud break, making it easy to select from canes that are producing healthy, new shoots.