First of all, grapes are pruned more extensively, and more aggressively than anything else you can think of. When you know how to do it properly, grape vines will become very productive. If you don’t do enough, it simply grows into a jungle and the plant is never as productive.
All you need to prune the vines is a pair of small hand pruners. If you haven’t been aggressive in the last several years, you may need a pair of hand loppers. The principle of pruning grapes is to leave four branches coming off of the main trunk. Usually there are two on the top with one going one direction, and one going the other direction. And again, then there are two lower branches with one going one direction, and one going the opposite direction.
Grapes are normally planted about twelve feet apart. So each branch is about six feet long. Then, the plant from the next trunk will be coming over, so the two branches are just about touching. Everything else that grew the previous year needs to be removed.
In selecting those four branches that we’re going to leave, you’ll need to get a branch that is about as big around as your little finger. Choose one that’s alive. You can tell that by simply trying to bend it. If it’s flexible and bendable, it’s alive.
We need to do the pruning sometime in the early spring, just before the buds start to swell. We’re a little bit late this year, because the buds are already starting to grow. We like to do that when there is just a small amount of growth developing. But, it needs to be late enough so that you can determine if there is any dead growth. You’ll want to be sure and prune it out.
Then, all you need to do is to measure off six feet. Pretend that this branch is attached to the trunk. We’ll measure about six feet from that and prune it off. Snap it off like that, and then everything else in between comes off as well. So any little side branches that may have formed come off as well. So, all we’re going to have is one cane coming off the main trunk – about six feet long, and nothing else on it.
A grape plant will produce a tremendous amount of growth in a single season. This is an example of one cane that grew last year. As you can see, it’s probably at least twenty to twenty five feet long. And the plant may have fifteen, twenty, or thirty canes that develop in a single season. The amount of wood that needs to be removed from the plant is impressive when it’s piled up.
The disadvantage of not pruning enough is that the plants produce a lot of foliage that becomes shade. This limits the plant’s ability to set fruit buds for the following year. So, you have a lot of foliage growth, and then it just becomes a jungle.
This is a grape plant that has been properly pruned. Here is the main trunk, and we have four branches going off in each direction. There are two at the top – one coming out here, and one coming out over here. And, there is one coming out down here. But as you notice on this side, we don’t have a cane coming out.
We can do one of two things. We can allow a cane that is coming from the other plant to go further to fill in the space. Or, if we can find two canes, for example there is one over here on the backside, we can simply bend around and tie it to the trellis, so that it will go in that same direction. Grape canes are very flexible, and they can easily bend around and move in any direction that you need to move them.
You may find a grape plant that hasn’t been properly pruned. In that case, you can correct it in a single season. For example, this is a cane that was allowed to remain from two years ago. It wasn’t pruned off, and it should have been. In this case, we need to take the entire thing off. It’s easier to remove it in sections.
Early on, when this vineyard was established, there was a plant that was planted here, and then it died. So, we don’t have a plant here. We have one six feet on this side, and about six feet on the other side. Rather than replace this plant, all we need to do is to allow those canes from that side to grow over a little bit further. Instead of cutting them off about six feet, you can let them grow from ten to twelve feet. As you can see from our cane that we pruned off, they’ll easily grow twenty-five or thirty feet. So, you’ll have plenty of cane, and we don’t have to worry about replacing this plant. There will still be plenty of foliage in here to produce grapes – even though the plant is missing.
If you read some of the manuals about pruning grapes, they talk about allowing approximately fifty buds to remain on the plant. These buds are spaced about six inches apart. So, when we talk about leaving that six-foot length, it means that we’re going to have about twelve buds along that cane.
Here’s a bud that’s forming right here. This will actually produce grapes this season – as well as this one, and this one, and this one. So, there will be a cluster of grapes about every six inches along this cane. There is one at the top, and one at the middle. New canes will form back off the trunk, or on a branch on an existing cane. Then, next year we’ll choose one of those good, strong, healthy canes as close to the trunk as possible, and then take off the one that grew this past year. So, this cane will produce one year, and then it will be removed.
Don’t worry if you happen to break off a bud. There are several buds in the grape cluster. If one happens to get broken off, or frozen, there will be another bud that will move in and take it’s place – usually up to about three buds.
This feature story prepared with Chuck Marr, Kansas State University Research and Extension, Horticulture Professor-Emeritus. For more information, visit your local county extension office or visit our website at KansasGreenYards.org.