Like any fruit-bearing plant or tree, grapevines need to be carefully but ruthlessly pruned. When making cuts to a grapevine, you can expect to remove about 90% of the year’s growth, which seems like a lot. However, in order to ensure the success of your garden, vines must be pruned and well cared for, so they produce plenty of fruit.
Failing to adequately control grapevines in your garden can allow them to become overgrown and unruly, producing a lot of vegetation but limited fruit. You have to train grapevines to get the most out of them, so you end up with enough fruit to make jelly or brew wine. If you’re growing grapes to ferment, check out the best winemaking kits. Properly maintaining your grapevines means you can control their growth and fruit production, and get a better yield when you harvest.
There are hundreds of different grape varieties, which may require slightly different pruning techniques. If you’re growing fruit to eat, your pruning method might need to be slightly different than if you’re growing grapes for wine, like Concord grapes. However, it doesn’t matter whether your grapes are sweet or seedless, they must be attentively cared for. Read on to find out about why it’s important to cut back your plants, and how to prune grapevines.
Before we jump in, let’s quickly explain the different terms and names you’ll need to know:
- Trunk: The main upright structure from which cordons, shoots, and canes grow.
- Cordon: A permanent horizontal branch from the trunk, positioned along the wire of your trellis or arbor.
- Shoot: A new green and leafy growth that produces fruit clusters
- Cane: A green summer shoot that has now matured into brown wood, after leaf fall.
- Fruiting wood: One-year-old wood that produces the current season’s new shoots and fruit.
- Renewal spur: A cane pruned down to produce a new shoot, to become fruiting wood next year.
Why should I prune my grape vines?
Grapevines only produce fruit on one-year-old wood, not new shoots or old growth. When a grape plant grows a new green shoot in spring, which turns to brown by the end of the season, this is considered one-year-old wood. Next year, this wood will grow flowers that develop into fruit, whereas older wood branches will only produce more leaves, shoots, and vegetation.
When pruning your grapevines, keep in mind the main goal. You want to maximize the amount of one-year-old wood on each grapevine, to produce as much fruit as possible. However, it’s important not to push your grape plants too far, as if you encourage them to produce too much fruit, it won’t have the resources to ripen them. Ideally, you want to find the right balance so you get a good crop from your grapevine, without endangering the quality of your fruit.
If you leave a grapevine unchecked, it’s likely to grow into a dense mass of old wood. There will be little one-year-old wood to fruit, and poor air circulation due to overgrowth can lead to fungal disease in your plants. When pruning, you can expect to remove anywhere between 70 and 90 percent of the previous year’s growth, so don’t hold back. It’s necessary to remove all but the bare bones of your grapevine in the winter so that once spring comes it has plenty of encouragement to produce a lot of fruit.
Grapevines are usually trained to grow on a certain structure, whether at home in the garden or in a commercial vineyard. For example, at the Rombauer Vineyards, grapevines are pruned according to each individual plant. When pruning your plants, you encourage them to grow in a certain structure. These grapevine structures are designed to make harvesting easier and to allow your plants to grow in a more orderly fashion.
Instead of a huge tangle of grapevines, training your plants to grow on a trellis will make every step of the process easier. When pruning, you can help your grapevine to conform to the shape of its trellis, encouraging an orderly and neat growth. Most vineyards use a trellis system with one main trunk and two or four main branches at 90 degrees to the trunk. These branches are supported by strong wires to help them hold shape.
Every winter, you’ll prune the grape plant back to the main trunk and branches, preserving the basic structure. Grapevines are extremely hardy and vigorously growing plants, so there’s almost no limit to the size and number of branches you want to use. Just remember not to encourage more fruit growth than your vine can actually support, so all fruit is ripe and ready by the end of the season.
What training system is best for grapevines?
The type of training system you use determines how you go about pruning, as you’ll need a basic shape or structure to stick to. Many gardeners use a high cordon system as it’s relatively easy to establish and maintain over time. A grape arbor is another choice, which can be a decorative feature as well as bearing fruit. Young vines will need to be trained with one or two main trunks, and then either head-trained with canes, with permanent cordons (horizontal arms) and the dormant canes pruned back to spurs, or in a fan shape on top of a grape arbor.
In a cane-trained system, each season new canes are laid down and head-trained at the top wire. You’ll notice new shoots in this system harden into canes about pencil diameter. Two of these new canes will need to be tied to the top wire, with one in each direction. You can tie down these canes using cloth, stretch tape, or twist ties, just don’t be too constrictive. At this point, you can also count the number of buds on the plant, and adjust them to your desired fruit load.
In a cordon-trained system, your approach will need to be slightly different. Each season, one-year-old canes should be pruned back to three or four buds per spur. If you’re growing a grape arbor, fruiting wood as one-year-old canes or spurs should be attached (tied on) to the top of your arbor.
Pruning different varieties of grapes
The type of grapes you’re growing has a huge effect on how you should prune your plants. For at-home grape growers, American and French-American hybrid grapes are easier to grow in your garden. These grape varieties are more resistant to disease and can push through the cold winter. Vinifera grapes take more experience to grow and are more commonly seen in vineyards than gardens.
Vinifera varieties produce less foliage and vegetative growth than hardier grape plants but produce more fruiting wood. American grapevines have the most vegetative growth, followed by French-American, so these grapevines need more pruning and maintenance.
The amount of wood you leave behind when pruning is determined by the amount of vegetation produced in the previous year’s growing season. You can use the 30+10+10 system to help you figure out what to chop off and what to leave. This can be used to calculate the number of buds you’ll leave on the vine, using the weight of already pruned-off one-year-old wood. Let’s look at an example:
- If you prune 3 pounds of wood of a vine, there should be 30 buds remaining for the first pound, and 10 buds each for the second and third.
- This means a total of 50 buds should remain on the vine.
- If more than 3 pounds of wood has been produced and must be pruned off, you’ll need to keep a further 10 buds for each pound.
This process is necessary to balance out the crop load of your vines. You need to ensure that enough buds remain on your plant to turn into fruit, otherwise, the vine will compensate with additional foliage. If there are too many carbohydrates for your grapevine to store in fruit, it will produce additional leaves and greenery instead. This is why you need to ensure enough buds are left on your plant, to maximize harvest as well as reducing your pruning work next year.
Starting off young grape plants
When you get a new young grape plant, it probably won’t be pruned or trained in any way. Most young grapevines have a vigorous root system beneath and a lot of bare shoots above the soil, not ready to be trained into fruiting plants at all. When spring rolls around and it’s time to plant new grapevines, you’ll need to cut it back to just one shoot, with only three buds.
Once you’ve planted a new grapevine, the plant will start to grow and push out new green shoots. Once the shoots are longer than 8 inches, select the strongest and securely stake it. Look out for an upright shoot growing directly from the old stem (never from the roots underground), and tie it on to support at the top and bottom. You’ll need to remove all the other shoots from the plant, so make sure you make a strong and healthy choice.
Through your new grape vine’s first summer, continue to stake it directly upwards. Make sure the shoot is secure and protected from breakage in the wind. This single shoot will be the permanent trunk of your grapevine for its entire life, so at this early stage it pays off to take care in training the shoot as straight as possible.
When to prune grapevines
Pruning should always be done in the winter season, for any fruit plant or tree. At this time of year, your plant is dormant, and the later you prune off old wood, the later new growth will start in springtime. However, this doesn’t mean you should prune early. Low temperatures can damage the wood and buds of most varieties of grapevine. In very cold weather, the wood of your grapevine is frozen and easily broken, so don’t risk this damage.
Wait until late winter or early spring to prune grapevines. If pruning is done too late in the dormant season, cut canes may drip or “bleed” sap, which is also harmful to the health of your plants. Usually, March is the best time of year for pruning grapevines.
If you were to prune during the summer, while the vine is green or growing, this could severely weaken your plant, and halt development. The green parts of a grapevine are where food is made for the plant, so removing these parts decreases the nutrition your vine will get. If you need to remove any buds or water sprouts that form once the dormant season is over, cut them as early as possible to avoid doing damage. You should never prune growing shoots or any other green part of the plant.
Pruning a grapevine for the first time
If you properly followed our instructions about starting your young grape plant, then after a year the trunk should have reached the first trellis wire, about 30 inches from the ground. If your plant hasn’t grown enough this first year, cut it back down to three buds and repeat the year again. This might seem like you’re removing a whole year of progress, but it’s necessary for the long run to establish a strong and reliable central trunk.
Most grapevines will easily reach the wire within a year, so if this is the case, you can continue with your plant’s first pruning. If the shoot just about reaches the wire or is just above, then cut it at the first bud. Tie this to the stake, and that’s all the pruning you’ll need. If your shoot is longer, you can tie it to the stake and wire, and cut four to five buds from this tie point. The remaining length of the shoot should be bent and tied to the horizontal wire in one direction.
If you have a particularly vigorous young plant, it could put out several strong side laterals above the wire in its first year of growth. If this is the case, choose the two closest to the wire, tie them on, and prune down to four or five buds once more. Tie the main stem or trunk to the stake, and cut it just above the side laterals. Pruning grapevines after their first year of growth is simple, it’s just about establishing a strong plant for the future. During the summer, train your new shoots to grow up next to the wire, and remove any that sprout too low, from the root area or lower trunk.
Pruning older established grapevines
As we’ve established, fruit on grapevines grows only on the green shoots from one-year-old wood. You base your pruning on the fruit produced in the current season, with the aim of renewing young canes for next year. Canes that produced fruit this season will not fruit again, so they have to be removed to make way for new growth.
There are several methods you can use to prune grapevines, with cane pruning the most popular. Spur pruning is lesser used, generally more effective with French hybrid grapes. Most of the time, American grape varieties should be cane pruned because of the climate, where extra vegetation will shade from the sun and make your fruit harder to ripen.
Cane pruning requires a permanently established trunk, and each year new canes are chosen at the head of the vine (where the trunk and trellis wire meet). Choose one or two canes on either side of your trunk, at 8 to 10 buds long. These should be tied to the wire, while all other canes are pruned away. When selecting canes to keep, look for a thickness about equal to your little finger, growing from as close to the head of your trunk as possible.
Buds should be reasonably close together, so avoid thick and long canes with more spaced out buds. You can also leave behind one or two spur canes pruned down to two buds each, to produce additional new canes. This will give you more choice when pruning next year, so you can select the strongest and have a more successful plant.
How to cane prune grapevines:
- Look for the best-placed canes for renewal, think about how the plant will grow in the next year.
- Choose the best quality and healthiest canes for fruiting.
- Decide how many buds you want the whole vine to retain.
- Cut back fruiting canes according to the vigor and size of the whole vine, to ensure new growth is properly supported.
- Remove all extra unnecessary wood, so your plant wastes no energy growing non-fruiting vegetation.
If you have a French hybrid grape variety, you’ll need to prune slightly differently. These grapevines produce more fruit near the base of the canes, so they require a different approach. For this type of vine, all the wood will be spur pruned, cut back to short spurs for fruit production and renewal both.
How to spur prune grapevines:
- Choose the best placed and most fruitful canes.
- Decide on the total number of buds you want on your grapevine.
- Cut your chosen canes back to two-bud spurs, and remove all the rest of the wood.
When pruning your grapevines, remember that you’re planning for the next year’s harvest. Make sure to remove all additional wood and canes, so your plant won’t waste energy in growing non-fruiting wood. It’s easy to maximize the fruiting potential of home-grown grapevines, whether you use a trellis or arbor.
Always calculate the number of remaining buds you’d like once pruning is finished, and plan from there. You can select the strongest and best-positioned vines for regrowth, removing everything else. Don’t be afraid to cut off the majority of your plant, every year when pruning it’s expected to remove about 90% of the previous year’s growth. If you don’t prune and maintain your vines, they can become thick, overgrown, and won’t produce much fruit.
On the other hand, properly maintaining our plants throughout the year will make every step easier, and increase your yield too. If you enjoyed this article, why not check out the best white wine cocktails, for your next summer party under the grape arbor.
Bonus tip: Check out this video for some ideas about pruning your grapevines in their first year!