Good Growing

Welcome to the Good Growing podcast. I am Ken Johnson, horticulture educator with University of Illinois Extension coming to you today from Jacksonville, Illinois. And this week on the podcast, we have a gardenbite. We're gonna talk a little bit about pruning fruit trees. So it's that time of year, time to start thinking about pruning our deciduous trees.

Most deciduous trees are gonna be best pruned while they are in full dormancy, which happens to be January through early March for this part of the country. While many of our landscape trees don't necessarily need to be pruned every year, the same isn't necessarily true for fruit trees, especially if you want healthy trees that are going to consistently bear fruit. If we just leave fruit trees to their own devices, they can quickly get too tall for to harvest the tops of the trees. We often get a buildup of disease and pests in our trees as well. So one of the reasons why we want to prune during the dormant season is that the trees will not have any leaves on them.

This makes it easier to see the framework of that tree, and we can determine what branches should be removed much easier than if there was a full canopy. Also, we prune too late in the growing season, as the trees are still growing, they may send out a new flush of growth, and this growth may not harden off before the winter and it can be killed. So dormant season pruning is going to be the best time for our tree fruits. Pruning is as much of an art as it is a science, particularly when it comes to tree fruits. So the art of pruning is being able to look at a plant and figuring out how to make the tree look the way you want, whether that's making it shorter, so on and so forth.

The science of pruning is being aware of the different cuts that you can make and how those are going to affect the plant and how it's going to respond to those different cuts. So when it comes to pruning fruit trees, there's gonna be several reasons we wanna do this. First is going to be to open up the canopy so that all branches are receiving sunlight. The more sunlight a branch gets, the better its fruit production is going to be. The more light, the more photosynthesis, the more sugars it can produce, the more energy it produces, the more of that stuff it can put into fruit production.

Second, it's going to help manage diseases and make pesticide applications easier. So opening up the canopy is going to allow sunlight and airflow in there. It's going to dry out that canopy faster, which is going to help reduce disease problems. Diseases like wet humid environments. So when they dry out quicker, it's less likely for diseases to develop because they do not have as favorable of conditions as they would normally have if we have a really dense canopy.

And with a more open canopy, if we're spraying our trees, it helps us get those pesticides into the inside of the tree better, so we get better protection from those chemicals that we're using. And then finally, by pruning our trees, we can keep our trees shorter so that it's easier to reach the fruit and harvest it. So the way you train and prune your fruit trees is gonna depend on the type of tree it is. Typically for apples and pear trees, we're gonna use a central leader system. So we're gonna have one central branch and then we're gonna have those scaffolding branches coming off the tree.

For peaches and nectarines, we're gonna use an open center system. So the tree is gonna look more like a vase. It's not gonna have that central trunk. It's gonna have multiple branches coming off that trunk. It's gonna make have a vase like appearance to it.

These aren't the only ways you can train your fruit trees, but these are going to be probably the most commonly used. So when it comes to actually pruning your trees, the first step is going to be to clean up the tree by removing any dead branches, any damaged branches, any crossing or diseased branches. When it comes to removing diseased branches, we want to make sure we're pruning back into healthy wood. So for example, for fire blight infected trees, we want to make sure we're pruning at least eight to 10 inches below any discolored bark. That way we are ensuring we're getting into healthy wood and removing all of those all that branch that is going to be infected by that bacteria that causes fire blight.

After we've removed those dead or damaged or crossing or disease branches, we can also go through and remove any suckers. Those are gonna be those upright branches, go in and remove those as well. So after we remove the suckers and any, any of those other branches that we don't want, then we can come in and start managing the tree size and the shape of the tree. And there's gonna be two different types of cuts we're going be using for this. We're gonna be using heading and fitting cuts.

Heading cuts are going be used to shorten and stiffen branches, as well as to increase branching in a tree. So this is going to be done by removing the end of a branch, typically prune that branch back to a bud. When we remove the end of the branch, remove the terminal bud. The terminal buds are going to release hormones that are going to prevent shoot development further down the branch and those buds further down the branch. When I remove that terminal bud, those slower buds aren't inhibited anymore.

So they will start to develop and you start getting a lot of branching below that cut location. So again, those heading cuts can cause a thicker, denser canopy, which can have some drop access, can reduce light levels within the tree, within the center of the tree. So heading cuts are going to be primarily used for establishing branches in young trees. We don't usually use them very often in older trees. If we do use them in older trees, we can use them to shorten and stiffen branches.

So if we have branches that are too pliable getting weighed down a lot with fruit, we can head those back a little bit and stiffen them up some. The second type of cut we're going to be using when pruning tree fruit is going to be thinning cuts. Thinning cuts are going to remove the entire shoot back to its point of origin. So unlike cutting cuts, these thinning cuts are not going to create a bunch of vigorous growth on the branches. These thinning cuts are going to help open up a tree's canopy, allowing more sunlight to reach the interior of the tree.

So for pruning mature trees, we're going to primarily be using thinning cuts to do this. We're pruning our trees, we wanna make sure we sanitize our pruners to prevent the spread of disease. We can use a 10% bleach solution, we can use isopropyl alcohol. We can use sanitizing wipes, any of that type of stuff. We want to make sure we're cleaning off our pruners, especially if we're doing multiple trees.

If you've got one tree, you can prune in between individual cuts if you want, but at the minimum, make sure you're cleaning your pruners. If you're pruning out disease plant material, clean those so you're not spreading any disease within the tree or from tree to tree. We want to make sure we're using sharp tools. Sharp tools are going to make cleaner cuts, which are going to heal faster than using dull tools. Nice clean cuts going to heal faster than a cut caused by a dull tool, which is crushing the material more.

It's going to make it harder for that wound to heal over. Once you're done pruning, we want to make sure we clean up and remove the pruned wood, especially if it's diseased and properly dispose of it, whether that's putting it out in the municipal waste, burning it if you can, if you don't have either of those options, can bury it in the ground, especially important for that diseased plant material. So it's not spreading from those branches you've pruned on the ground, leave them on the ground. We don't want that to spread back onto our trees and cause us problems down the road. Now, if you have a large tree that's been neglected for several years, so you've got an apple trees or say for example, you've got an apple tree, it's been growing in your yard, you haven't pruned it for five, ten years.

You don't want to go in and just prune that back really hard, get it all cleaned up really quick. It's best to rejuvenate or renovate that tree over a period of three years. So when it comes to rejuvenating or renovating trees, we want to make sure we don't remove any more than one third of the tree per year. So we'll slowly get that tree back under control. We don't want to just go in and remove everything.

Removing too much wood is going to set that tree back. So do it slowly over a period of time. This will help prevent excessive sucker formation, as well as sunburn to previous previously shaded areas of the tree if we do this slowly over a period of three years. Well, that's all I've got for you for this week's Gardenbite. The Good Growing podcast is a production of University of Illinois Extension.

Listeners, thank you for doing what you do best and that is listening. And as always keep on growing.