Muscadine grapes (Vitis rotundifolia) are native to southern North America and have been cultivated since colonial times. For owners of these wonderful fruits, knowing how to prune muscadine grapevines properly is a must. Without proper pruning, muscadines are doomed to become tangled masses of woody vines bearing little or no fruit.
Old wood must be cut away to make room for new growth, as it is new growth that produces fruit. Vines with too much old wood will not bloom and bear fruit. Those with too much growth will not produce well either. Therefore, pruning muscadine grapes not only controls growth, but also increases the productivity of the plant.
Before you can discuss how to prune muscadine grapevines, it’s important to understand the vine’s natural growth and the framework that should be imposed upon it.
The vine framework is comprised of the trunk and two or four permanent cordons (arms) and fruiting spurs. Pruning muscadine grapevines each dormant season maintains this basic form. New shoots — those grown in the current season — are the ones that bear fruit. These new shoots, however, rise from last season’s growth and a balance must be struck when pruning.
Grapevines, old or young, benefit from late winter or early spring pruning. The same process for pruning muscadine grapevines is used regardless of the type of trellis they are trained to. What’s important is to begin properly and avoid problems later on.
For new vines, pruning begins as soon as the root is planted and continues through the first two growing seasons. Cut the trunk stem back to two or four buds. Tie the trunk above or between the buds to the trellis wire. As the trunk grows, clip out the side shoots that develop, but leave the leaf growth along the trunk alone. Repeat the side shoot trimming throughout the summer.
Over the first and second growing season, keep pruning away at unwanted growth until the trunk is taller than the wire. Now is the time to prune the terminal (topmost) buds back to wire height and let the new topmost buds develop into the cordons. Trim back lateral (side) growth on the cordons to one foot (0.5 m.) lengths to encourage rapid growth and development.
From here on in, trimming muscadine vines will be a dormant season chore.
January through February is the ideal time for pruning these vines and the process is fairly simple. Once the basic framework is established, pruning is used to develop short lateral shoots, or spurs, off the cordons.
All shoot growth from the previous season should be cut back to spurs with two to four buds each. Over a number of years, as the spurs keep sending out new shoots, the vines develop spur clusters. When there are too many spur clusters or the clusters become too large, the shoots will become weak and the fruit sparse. When this occurs, pruning of muscadine vines should also include the partial removal of heavily spurred clusters or the compete removal of every other overloaded cluster. Often, these vigorous spurs are found at the top of the trunk and most of the spur system should be removed. Vines may “bleed” at the pruned sight, but this won’t hurt the plant and should be allowed to heal naturally.
Another growth to watch for while trimming muscadines is girdling. Tendrils will wind their way around the trunk or cordons and will eventually strangle the trunk or lib. Remove such growths yearly.
There is one more area that should be covered: how to prune muscadine grapevines that have been neglected and are seriously overgrown. You can start from scratch and cut the vine all the way back to the original trunk with drastic pruning. Muscadine grapevines are tough and most will survive the shock. However, to keep the vines producing while you bring the plant back under control, you might consider pruning only one side of the trunk or one cordon at a time. The process will take longer — possibly three or four seasons — but the vine will retain its strength and productivity.
The scuppernong grape, also known as the muscadine grape, is native to the Southeastern United States. Scuppernongs grow well in the region’s warm and humid climate, their vines growing 60 to 100 feet. Much of the work that goes into caring for scuppernongs centers on pruning the vines properly. Heavy annual pruning of the scuppernong vines ensures healthy and bountiful fruit production. Also, pruning assists in training scuppernong vines on the trellis.
Prune your scuppernong vine back to one stem after planting it. Cut the remaining stem back to two or three buds, or “spurs.”
Choose the strongest shoot and cut away all the other shoots after new growth begins. Tie the shoot loosely to a stake placed beside the scuppernong vine plant. Remove side shoots from the main shoot every week.
Cut the growing tip when the vine is just below the trellis wire. This will force lateral buds, which you can train down the wire.
Prune back the side shoots to two or three buds during the first dormant season. Leave the one-year spurs about 6 inches apart.
Cut back all lateral shoots to two to three buds during every dormant season thereafter. Prune back all shoot growth from the past growing season until you’re left with fruiting spurs 4 to 5 inches long.
Thin the clusters of spurs that develop after the fourth or fifth fruiting year. Thinning of these spurs will encourage new spur growth, bearing healthier fruit than the older spurs.
While pruning your scuppernong vines, watch for pests like leaf hoppers, aphids and flea beetles. Also keep an eye out for fungal diseases, such as bitter rot, powdery mildew, angular leaf spot and black rot on the fruit, leaves and flower clusters.
Don’t make your trellis so tall that you can’t reach the upper vines and shoots. Scuppernong vines require regular, aggressive pruning, so you’ll need to be able to reach the entire vine easily.
Pruning grapevines is an essential step to having healthy vines. Pruning should be regular to encourage new growth. There are two main methods for pruning your vines – Spur and Cane pruning. Choosing the right method depends on what kind of grapevine you have planted in your garden.
For most European and muscadine grapes, excluding Thompson Seedless and Lady Finger, use Spur Pruning. With this method, you cut back your dead growth to create short “spurs” where the new growth will start. These spurs should have one to “canes” where the fruit and leaves will grow. Once the fruit is born and harvested, the canes will be cut back so new spurs will grow.
Use the Cane Pruning method for Thompson Seedless, Lady Finger, Concord, and Niagra grapevines. These vines rely on buds on the far ends of their canes to produce fruit, thus, if they are cut to spurs, their production will suffer.
There are specific steps you must take each season to grow your grapes into a mature plant. For the first three growing seasons, the steps are the same. In the third dormant season, the methods of spur and cane pruning will come into play.
In the first growing season, plant your vine and let it grow as it chooses. A healthy vine will grow several shoots.
In the first dormant season, during the winter, choose the best shoot, which is usually the thickest, and prune all the others around it to the base of the vine. Make sure you have your trellis buried close to this shoot to guide it’s growth. This will be the trunk of your vine.
In the second growing season, let the shoots grow to about 12 inches long. Choose the healthiest shoot, often larger in diameter and closer to the trunk, and pinch off the others where they connect to the trunk. Tie the one shoot to the support and guide it to grow upward toward your wire. Once it is close to the wire, pinch it to stimulate branching. Let another strong shoot near close to the wire branch on the other side, so your vine begins to grow in a T shape. These will become your main branches. Pinch off all the others that are 8-10 inches long.
In the second dormant season, cut away all the shoots to leave only the trunk, and the two main branches. Tie the branches to the trellis wire.
In the third growing season, let the vine grow, pinching the tips of sprouts on the trunk to stimulate growth.
Spur Pruning – Third Dormant Season and Beyond
In the third dormant season, cut away all shoots that have grown on the trunk. On your two main branches, find the strongest shoots. Prune the shoot so that everything but two buds on the branch are removed. These will be your spurs. Space the spurs out 6-10 inches, making sure every spur has two buds. If there are weak shoots at the base, prune these away.
Your grapevine will be established by now, so every dormant season after this will be the same. Each spur will produce two shoots that bear fruit during the growing season. Prune away the weak spurs, while cutting the stronger spurs down to two or three buds, which will produce fruit in the summer. Keep the trunk clear of any new shoots. Repeat this process every year.
Cane Pruning – Third Dormant Season and Beyond
In the third dormant season, cut away all shoots that have grown on the trunk. Prune everything but two long shoots off the two main branches. These two shoots that remain are usually closer to the trunk because they are the healthier shoots. The shoot that is farther from the trunk should be tied to the wire. Prune the farther shoot to two or three buds. The shoot that is tied to the wire will bear the fruit in the next season, while the shoot you clipped will grow to replace the tied shoot and produce fruit the season after next.
Every year after this, prune the cane that produced fruit to the stub, which should have two or three canes growing off it. Choose the best cane and tie it to the wire – this cane will produce the fruit the next season. The weakest shoot should be removed at the base of the shoot, so there are only two canes left. The cane that is not tied to the trellis should be pruned to two or three buds, to prepare it for bearing fruit the year after next. Repeat this process each year.
Grapes must be pruned every year to keep producing because once a cane has fruited, it doesn't fruit again. Fruits form only on buds that arise from the previous season's growth. Which pruning method you choose depends on the type of grape and variety you have and which seems convenient and efficient to you. For American grapes, the most widespread system is the Four-Arm Kniffen System. For the vigorous muscadine grapes grown in the South, a two-arm version of-the Kniffen System prevents excessive leaf shade.
European wine grapes are generally trained to have two permanent arms and are spur pruned. If you have only a few vines and don't want to put up a wire trellis, you can head-train European grapes instead.
Pruning is done once a year-after the coldest part of the winter. Be sure to cut back to firm, live wood the tips are often killed back. Muscadines are usually pruned after the first severe frost in the fall.
The first few years are the same for the basic systems, the goal being to produce a strong root system and trunk. Here are the steps:
1.When planting, cut the vine back to two or three buds. It's a good idea to place trellis stakes or posts by the vine at this time the wire can be put up later.
2.Early in the first summer, pick out the strongest growing cane and let that one grow. As it gets taller, let several side shoots develop off the main one where you intend to place horizontal supports.
3. The following winter or early spring, prune back all canes as shown. Leave three buds on each of two or four lateral spurs (depending on how many arms you want). Put up wire supports.
4. The second summer, tie the side shoots to the wires as they grow. Remove flower clusters - you don't want the vine to fruit yet. Also remove shoots from all buds except those on the spurs.
Four-Arm Kniffen System
Choose four healthy, well-spaced arms to train on the wire for fruit production. If they are very long, trim back to ten buds. Choose four more canes for renewal spurs cut these back to two buds. Remove all other canes. The following summer, the buds on the fruiting canes will grow into long shoots, each bearing two to three bunches of grapes. The buds on the renewal spurs will also produce shoots if they are vigorous, let them fruit. If not, remove their fruiting clusters.
Remove the canes that fruited and choose one replacement from each renewal spur to tie to the wires. Trim to ten buds. Cut back another four canes to form renewal spurs. Your vine should now look approximately as it did a year ago. Repeat each year.
In this system you develop two permanent arms with spurs that produce fruiting wood each year.
Remove all canes except the best two tie these to the support wire. The next summer each bud along the arm will send out a fruiting shoot. Weave these in and out of the upper wires.
Check the horizontal branches for the strongest vertical shoots and cut each of these back to two buds. These wilt be the fruiting spurs. Space them about 6 to 10 inches apart. Every bud you leave on the spurs will produce a fruiting shoot the following year. Each year, repeat the process.
Spur Pruning: Head-Trained
For this system, the vine will need only a strong, vertical, 4-foot post for support.
1. Allow the vine to grow to the top of the post and cut just above that point. Tie to the post. Remove any branches below. Next year, let four or five branches grow.
2. In the winter, cut each of the branches back to two or three buds. Remove any weak branches and any on tower parts of the trunk. Buds left on spurs will produce fruiting shoots next year. You can allow more branches to develop as the vine matures so there will be more fruiting shoots each year. A mature head-trained vine can have more than seven main branches.
How you train your grapes will depend a bit on which trellis system you decide to use and what types of grapes you’re growing. For the most part, using a small bamboo pole or a stake in the ground next to your vine and tying a string or wire to it to connect it to the trellis above will work. This will provide your young plant with proper support as it grows up toward the trellis wire. You may need to attach the vine to the support with garden tape or string.
There are many ways you can grow and train your vines, just make sure you have your trellis in place before you plant your grapes. While arches and pergolas are a beautiful option they can make it harder to maintain the vines and will inevitably decrease fruit production. It is important to have access to the cordons, or arms, of each vine to prune them on a yearly basis if you want maximum fruit yield. Choose a trellis system that works for your space and desired outcome.
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A double wire system will yield about 30% more fruit than a single wire trellis and can be used if you have more space in your yard or orchard.
Double wire trellis supplies:
No matter what type of trellis system you choose for your grapes, one of the biggest keys to a successful harvest is maintaining vines. Be sure to prune back appropriately, based on the type of grapes you’re growing. Many grapes are area specific, so don’t forget to utilize your local cooperative extension office for great info on the grapes that grow in your area.