Four Arm Kniffin System for Growing Grapes
David Handley: I'm David Handley, vegetableand small fruit specialist with the University of Maine Cooperative Extension. Today we'regoing to be talking about a simple system for pruning hardy grapes here in Maine. The pruning system I like to use is very simple.It keeps the plant open, so it gets light in the summer time, but it also protects theplant a little bit in the winter. This system works best with concord type or labrusca typegrapes, which are the grapes that tend to grow best in Maine. There's really a couple of systems that willwork well for labrusca type grapes. The first
one I want to talk about is the four arm kniffin,and that's what we're going to prune first. The four arm kniffin consists of a perennialtrunk, which goes from the ground right up to a top wire, which is set at about fivefeet. Coming off of this trunk, we will have four arms, or canes, oneyear old growth.Two on the top wire, running each side of the top wire, and two on a lower wire. Thislower wire should be set at about two and a half feet off the ground. Every year, we're going to come in and pruneit so we continue to have a perennial trunk, but only four one yearold trunks to producethe fruit.
Here is our permanent trunk. You can see here,this is a cane from last year. Two yearold cane, this was our fruiting cane last summer,and you can see the difference. Here's this year's cane, that nice chocolate brown colorand smooth bark, and here we go with the older cane, the two yearold cane. The bark is startingto peel, and has more of a gray look to it, so we know that this particular shoot isn'tgoing to fruit again. It's the one yearold shoots that come off it that will fruit. This is going to get pruned out, so that wecan keep our fruiting wood closer to the trunk. We'll just take that back to a good fruitingshoot, and we'll start to cut it out. This
is where it gets fun. We need to wrestle thisout of the trellis, and of course, all these little tendrils have tied it up and aroundmost of the growth that's there. It takes a little bit of cutting, but be careful notto break the fruiting canes that you want to leave behind. Pull it off, and that will open the plantingup so we can see what we have left for good fruiting wood for this year. We've taken offthe four fruiting canes that we left last year, and you can see pretty much all that'sleft, at this point, is the green shoots from last year, that will provide us with goodfruit for this year.
Now we need to choose which four we want toput up. We're going to have four canes. One, two, three, four. Two for the lower wire,two for the upper wire, each heading off in different directions. What I want to look for in this case is canethat's got this nice chocolate brown color, and is about 38 of an inch in diameter. Aboutthe width of your little finger. If it's thinner than that, if it's very weak, it won't producegood fruit. Thin stuff like this, less than 38 of an inch in diameter, we'll just cutthat right out. Here we've got one that's going to go in thisdirection, that looks very nice. I'm going
to count, remember we want about 10 buds onit, so we'll count our buds. One, two, three, four, five, six, seven, eight, nine, 10. ThenI just cut out beyond that, because the weaker stuff at the very end isn't going to producevery good fruit. I have my four arms, but you can see I stillhave some leftover canes. What I'm going to use these for are what we call quot;renewal spurs.quot;I'm going to cut these back so that they just have one or two buds on them. What I'm goingto use these buds for, the green shoots that will emerge from these buds and grow out,will be the canes that I'll be putting on the wire next year for fruiting. We call thesequot;renewal spurs.quot;
Well, spring has finally arrived and it'sa great time for us to consider pruning out crapemyrtles. And it's a great time for tworeasons: one is, we've passed the most severed part of the winter and if there were any winterdieback it would be very visible. The second reason is there are no leaves so it's veryeasy for us to see the branch structure of our plant. Now before we get started, we probably shouldreview some of the common tools we need before pruning our crapemyrtle. First off, you probablyneed a very nice pair of leather gloves. Second, you really need a good pair of handprunersor handshears. I also find it very helpful
in pruning crapemyrtles to have a pair ofloppers. Essentially it's a pair of hand shears with longer lever arms. And it's kind of optional,but I find it very useful to have one of these saws with the teeth kind of exposed. Thistool can work its way into this crown very easily. In contrast to a bow saw, which Ireally can't get into the interior of this plant. So these are some of the common toolsyou'll likely need for this project. We're going to use two pruning techniquesto prune a crapemyrtle. One is Renewal Pruning and the other is Selective Thinning. So, RenewalPruning, what is ité What we do is, we're looking to remove entire branches or stemsall the way down to the ground level. So this
branch, it's more than what we need for thisparticular plant plus it's bowing out from the plant. So all we're going to do is useour loppers, and get it as close as we can to the ground and we'll simply cut. We can also use a saw for Renewal Pruningand again the objective is to simply cut the branch off as close as we can get to the soillevel. The other technique we want to use is SelectiveThinning. And that simply involves removing a lateral branch all the way back to its pointof attachment. So, we're going to follow this branch back to its point of attachment andwe're going to make a very clean pruning cut.
This particular branch is a very good exampleof why we use selective thinning. This branch is starting on one side of the plant and thenit's crossing back through the center. So it's causing lots of conflicts in this plant.So we're going to remove this using Selective Thinning. Using these two techniques of Renewal Pruningand Selective Thinning we're going to go ahead now and prune the rest of this crapemyrtle. Many people find the seed head objectionableon crapemyrtles, so if you feel that way, there's no problem with just snipping thatoff and be done with it.
Well, we're just about done, one more cut.And notice that we've achieved our objective of maintaining the natural habit of the crapemyrtleusing those two techniques, Renewal Pruning and Selective Thinning. Now the majority ofpeople in this state simply quot;topquot; their plants at about four or five feet. They just cutall these branches off. And it really makes the plant look ugly in the winter time. Overall this pruning project took us about5 minutes and we removed about that many branches from this plant. We achieved our objectiveof maintaining the natural habit of this crapemyrtle using those two techniques, Renewal Pruningand Selective Thinning.
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