9UNP1219SD_Jackie_Askins

- Good morning, and thank you so much for joining us this morning. My name is Jackie Askins. I'm with the University of Wisconsin-Extension, Cooperative Extension, and I am very pleased to introduce Lisa Johnson. Lisa is the Dane County UW Extension horticulture educator, and she will be talking with us this morning about proper tree planting. So please welcome Lisa. 
[ applause ]

- Hi, and thank you for inviting me today. It's nice to see everybody. 

My name is Lisa Johnson, and I work at the Dane County Extension office. One of the things that I do is I teach master gardeners. And this presentation was put together by my colleague, Mike Maddox who works in the state program office, and myself, to teach master gardeners how to properly plant trees, and I hope you will find this information helpful for you. So, trees are very important, and we actually live in something called an urban forest. Those trees that are planted on municipal terraces, next to your house help do things like cool your house. They help control rain water, storm water flow. They do cooling of your house. They do a lot of things for us in terms of air quality. Trees by way of photosynthesis will actually sequester carbon, so the carbon that gets into the air from buses and cars and so on get absorbed by leaves. So trees are really important in our lives, and when we don't have them because of things like Emerald ash bore, we really start to notice it. 

So this presentation then is geared towards properly planting trees so that we can keep them around for a long time. What I'm going to be doing is talking about the various facets of planting. So the first thing, the most really important thing is that we choose the right plant for the right place. And so we will talk about that, then we'll talk about roots and root flares and the importance of getting those at the right level when we plant the tree. We'll talk about planting materials and planting methods and then, yes I know it seems like a no-brainer, but actually how to dig a hole is different now then when I was an undergraduate. They have done research that has shown that if you dig a hole in the old way that I was taught that it is not as beneficial for the tree's survival over the long haul.

So, the right tree in the right place is a principle that just involves matching the appropriate tree to the appropriate environment. And the things that we need to consider, one of the first things that I tell people is to look up. Are there power lines? Because that's something that a lot of people forget because it's not really at your eye level. 

And it's really important to know if there are power lines because I'm sure you've all seen in municipal settings the "V" prune trees that have had to adapt to be severely pruned because somebody didn't think about how tall the tree was going to get before the wires were put in. So we want to think about tree heartiness. Is the tree going to be hearty for your environment? Is the appropriate light available? Some trees prefer partial shade. Some prefer full sun. What is the pH of your soil. pH is a measure of alkalinity and acidity. There are some trees that prefer more alkaline soils and in south central Wisconsin, southeastern Wisconsin, we tend to have more alkaline soils. Farther up north, we tend to have more acid soils. 

So you want to make sure that your tree is well adapted for the soil type that you have. What's going to be the eventual size and width of your tree? This can be hard to determine because trees actually don't stop growing until they die. So when somebody says, "Well, how big is it going to get?" I can say, "Well, how long are you going to be at the house." Or I can say, "This is a typical growth rate, and I can tell you what it usually will grow per year." But I can't necessarily tell you what the eventual size is. I can say it's a medium tree or a large tree, but it's really hard to actually come up with a number. What is the growth rate? What is the potential for littering? 

One of the municipal trees that people who work with the cities and villages and so on and parks that have to clean up after trees really hate walnuts because they dropped these big honking nuts. There are also trees called Kentucky Coffee Trees that have very long leaf rachises and when the leaves are shed in the fall, these things fall and they lodge in the grass, and you have to rake them out, and it's a big pain. Also, if you have a tree that has berries, and you've put it over a sidewalk, that creates all kinds of mess and problems. So, that's something else to think about with your particular setting. And finally is the tree very susceptible to diseases or insects? There are a few trees that I never recommend because I know they're short lived or they're very disease prone. Right now, unfortunately, we don't recommend ash because of the emerald ash borer. So there are-- doing your research is a really handy thing to think about. And then looking at the site. So once you've chosen the tree, matching it to your site. 

What is the soil type and drainage again, pH above ground, below ground, utilities. Definitely this is the time before you buy the tree to call digger's hotline and have them make sure that there isn't a utility line right where you want to plant because that's really annoying if you got the tree home, and you can't put it where you thought you were going to put it. Surrounding structures. Is your tree going to grow into a garage or your house or is there a fence nearby. So you want to think about those things and then lines of sight. As this tree gets bigger, is it going to block you as you're trying to back out of the driveway and you can't see because this big trunk is in your way. So all of those are different pieces of a puzzle that go together to form right tree, right place.

Another thing to think about is from the tree's point of view do you have enough root space. I'm sure that if you've looked at a tree in a parking lot you will soon realize that that tree is under a lot of stress, and it's primarily because it does not have a big enough root zone for its roots to spread out. Root systems actually generally spread about three to five times the height of the tree. 

Now, the primary root zone may be more within the drip zone of the tree. And the drip zone is where the rain runs off the canopy, so at the ends of the branches. That's the drip zone. But you still should think the tree would prefer much more room than that, so putting a large tree in an area that's right next to a sidewalk, a driveway, that kind of thing where it's a paved surface and the tree is going to have trouble getting its roots to grow in there is something to think about as well. Also, 90% of the roots are in the top 12 inches of soil. So, you don't want to be planting a tree if you're out in a rural area and vehicles get parked under the trees. Keep in mind that you don't want to compact that soil. And the reason for that is that compacted soil is really hard for roots to grow in, and one thing that is the reason for that is the compacted soil doesn't have a whole lot of oxygen in it, and the reason the tree roots grow in the top 12 inches of soil is that's where the oxygen is, that's where the nutrients are, and that's where the water is as well.

Once again, don't forget the call digger's hotline. It is open 24 hours a day, seven days a week, and it's pretty easy to get a hold of. 

You can even go to their website.

Here's an example of a tree that was not planted in the right place. You can see that it's got a very restricted root zone. This tree was obviously under stress. I'm not sure why that branch broke off, but they did a terrible pruning job, and clearly this tree is now what we call in the trade a hazard tree. I would not want to be parking my vehicle next to that tree. I would not want to have my house next to that tree. I don't even want to walk near that tree frankly. That tree is probably hollow on the inside, and is just an accident waiting to happen at that point. This slide shows a really good example of trees planted in not so good places. 

So wrong tree in the wrong place. And the picture on your left is a poor tree that got planted in a parking lot. And it isn't even in a bed as you can see. It's right in the ground, and somebody got the brilliant idea that it would be a great idea to run asphalt right up to the trunk. So not only can the poor not absorb any water, but you can see that it's been banged into by cars a number of times. Not long for this world, I fear for that tree. The picture on your right is a Pin Oak. You can see that the leaves are kind of a yellow kind of off color, and that is what we call chlorosis, and that is due because that Pin Oak is planted in soil that is too alkaline. And so there are a number of trees that are very sensitive to pH like that. River Birch is another one. 

Some of the maples are very sensitive to pH too. So when you see an overall cast to the leaves like that, I would get a soil test done to see what your actual pH is. A couple of more examples of wrong tree in the wrong place. Also a really good picture of bad pruning. The picture of the trees under the power lines, clearly those trees are too tall to be planted in that place, and whatever entity did the pruning did a really bad job of pruning so that has compounded the issue. And then in the lower right corner there, we've got a picture of black walnut. The nuts on those, they can be not only a tripping hazard, but black walnut is a tree that has what we call allelopathy, and that is that the root system puts out a chemical called juglone, and juglone inhibits the growth of other plants. So it is a way for the tree to out compete its neighbors, and if you are trying to plant tomatoes or lilacs or a bunch of other plants near the root zone of a black walnut, you have probably had issues. A lot of times when people call me up and ask why their tomato isn't doing well, one of the first questions I ask is do you have a black walnut in the area. So all of this goes into your right tree in the right place. 

Okay, the next thing is choosing quality stock. I know that all of us are picky about our trees as we should be. You want to make sure that your tree has good branching and good architecture. What do I mean by good architecture? Well, good architecture means that there isn't more than one branch coming out in one place. I have a tree in my backyard that I did not plant, and I wish whoever planted it had not because it has about five branches all coming out at the same area. That is not structurally sound. So that is poor architecture. You also want a tree if it is a shade tree that has a single leader. It's not so important with the crab apple or some of the smaller trees, but it is important with a shade tree. 

And if there are any signs of insects or diseases, usually I'll check the trunk. I'll make sure that there aren't any sunken areas, discolored areas. I'll look at the branches, look for any breaks or anything like that. One thing you might want to do is if it has a cardboard sleeve on it is check under the sleeve because that can hide a multitude of issues. If the stock has been poorly maintained, under-watered, a lot of those bargain trees that are on sale at the end of the season are not always bargains they had a lot of stress put on them during the season. So you might want to think about that. And then finally, origins from Southern climates. If it says on the tag that it came from Tennessee or Georgia, the Carolinas, that tree probably is not going to do very well here. There's an issue called provenance that where the seed stock for that plant came from-- if it came from a Southern area, it may not do very well in this area even though it's the same type of tree that does grow in this area. So where the tree was produced is important. 

Now unfortunately, it's not always easy to find that information and many times the-- particularly if it's a big box door, they may not know where the tree was produced.

So this is what a good healthy tree should look like. You have strong, well developed leader, that's the central leader right here. This is the central leader. You want to make sure that the branches are well distributed around the trunk, and you want to make sure that there aren't any branches that are over 1/3 of the size of the trunk because that's unbalanced, and between the two branches going up and down, you want to make sure that you have good separation so they should be about 8 to 12 inches. And then good trunk taper. And we'll talk about why that's important later. Also, wide crotch angles. This tree has good, at least 60 degree crotch angles where the trunk and the branch meet. That's called a crotch angle, and if it is a V-shaped crotch angle, that tends to be a lot less sturdy. 

Now, some of our trees like Autumn Blaze Maple, Silver Maple tend to have V-shaped crotch angles, and those tend to be also more weak-wooded trees, so it's a good thing to check on that.

Okay, now we'll go into actual planting. This is the method that a lot of people use for planting trees, and it really is going to cause problems in the future. This was once what was recommended where you just dig a hole and you stick the tree in. You don't do anything with the ball or with the burlap, and just plant it, and that really is not the best way to do things.

So this is what is recommended these days. You dig a wide shallow hole. You make sure that the bottom of the root system is resting on the hole . You don't put any amended soil in the hole. You just us soil that is native to the site. 

Of course, you've already chosen the right location and the right tree so that's a good thing to start out with. The sides of the hole should be sloped, and they should be roughened a little bit particularly if you're in heavy clay soil. Now a lot of folks in southern Wisconsin do have heavy clay soils, and if it's heavy clay compacted soils, that's even worse. So, what can happen with that is if the sides aren't roughened, if they're glazed like a ceramic pot, it's really hard for the roots to penetrate into the surrounding soil. So you do want to make sure that you do get that roughened up a little bit. Proper planting starts with finding the root flare of the tree, and that area where the trunk flares out and you can see that very well in this picture. It's harder to find in a younger tree, but where the root flare is, that needs to be found and needs to be-- that's your top level. That needs to be either at or slightly above the ground level at the time of planting. Now, the problem is that it isn't always there at the top of whatever planting medium you're using. So you can see these trees were probably planted by squirrels. 

Squirrels did an excellent job planting these things because the root flares at the right level. Maybe they didn't get the angle quite right. Some of those trees are leaning a little bit, but they did at least get the right level. And that root flare is important for the support of the tree. It also stores a lot of nutritive tissues and it should not be buried. Trees particularly oaks are very, very sensitive to grade changes. I went out to a site once because I was asked to by an arborist who said that the trees were dying, and he was pretty sure it was due to construction, but the developer was saying, "No, no. It's oak wilt." So I go out to the site, and what do I see but bobcats running over the root zones of these trees. They didn't have any fences put up for construction. 

They had piled a foot of fill in some of these areas. Now, I looked at that and I looked at the symptoms of the leaves, and I'm like, "This is not oak wilt. This is a clear case of death by construction, and it was really sad because this was a new condo area and clearly it had been chosen because it had all these mature oaks in it. And they had just not thought about the biology of the tree or bothered to protect them.

So this is what I mean by deep planting. If you don't have that root flare, and you can see that the root flare is at the top of the root system, but it's not at the top of the ground, is it? So, the roots have a couple of choices. The first one is they can suffocate and die. The second one is that the roots can try and adapt by growing upwards. Remember roots like to be in that top foot of soil. 

So once they start growing up instead of out you may get something that's called girdling roots, and girdling roots are roots that curl around the trunk of the tree and can actually strangle it, and it's much more common than you might think. One thing I can tell you is that after this presentation, you will see a whole bunch of trees that have been incorrectly planted. And this is one of your clues. When you look at the tree, if it goes into the ground straight like a telephone pole, it is planted too deep, but if like the tree in the background you see a nice flare on it, you know that at least it's been planted at the appropriate level. So what does deep planting do to the tree? Well, it's roots and it's root flare are too deep so it is struggling for oxygen. It's struggling for nutrients. It's struggling for air, and so what tends to happen is the canopy starts to thin out over time. It may not happen right away. It may take five years. 

It may take 10 years. You'll start to see early fall coloration. You'll start to see leaves that are smaller than normal. You'll start to see branches that don't grow very much. You might see dieback. And often you can see the girdling root going around the base of the tree. Unfortunately, there's not really a good remedy for it. There is-- arborists can try using an air knife which is a-- it's basically compressed air that is forced into the ground, and they try and excavate around the trunk, but the problem is that the girdling root is really big and it's been there for a long time, it may have already done too much damage to be repaired. So these are some deep planting symptoms. These are the same kind of tree planted at the same time, and you can see that one of them is really thin. 

It's already turning color. The other is full and lush and looks like a tree ought to look. Another example of premature fall color, canopy is thinning and if you can see the base of the tree, which you can't because of the hostas growing around it, you would see that it grows straight into the ground like a phone pole. So this is what it actually looks like, those girdling roots. Now they've removed the one root that was actually girdling the trunk. But you can see why that would be a problem. The tree's vascular system which allows it to take water up through the roots in the soil and move it around the canopy of the tree is right underneath the bark. So when you compress the bark, you damage the vascular system which explains the dieback and the early fall color and small leaves, etc. Sometimes it will also cause rotting at the base of the trunk. Some other things you might see. 

You might see cracking. Again, that trunk compression instead of going out, the trunk is going in, and that's from that pressure from those girdling roots.

Another thing that can happen is sort of a ball and joint system that starts going when you have girdling roots that compress the trunk tissue.

So this is what the air knife looks like in action. Somebody else has actually tried digging out as kind of a home remedy with a trowel and you can see from the soil line there the light colored area on the bark where-- how deep that tree was planted. You can't even quite see where the root flare is on that tree.

So trees are sold them in three different ways, either bare root, balled and burlapped like in the picture here or in a container and in each situation you need to find the root flare. This sounds a lot easier then it is. The easiest one is the bare root. And because the roots are bare, you can easily identify that root flare. 

So there are good things about bare root and not so good things, and the same with balled and burlapped, otherwise called B&B or containerized. The root system for a bare root plant-- again, you can see if there are any broken roots. You can find the root flare. It's very light and easy to carry around, but typically they're only available as bare root really early in the spring, and you want to plant them while they're still dormant. Usually there isn't a great choice in terms of different varieties of trees so if you want to plant bare root, you kind of have to go with what's available at the time.

This is a little bit better shot of what a tree might look like if it's bare root. In this particular case, the tree is grafted. Not all trees are grafted. Fruit trees are all grafted, however. So the scion, you can see the label up there on the right hand side at the top, that contains the trunk and branches of the tree, and then there's a graft union where the scion is connected to the root stock. 

And below that, is where the root flare is. So you can see where the planting level ought to be. Now, a lot of people might actually mistake the area where the graft is as the place that they ought to plant the thing. And you need to plant it again where the root flare is. That needs to be at ground level or slightly above.

Balled and burlapped trees, not so easy to find the root flare. In many cases, you might have to excavate that ball, so usually that's going to require a little bit more work. Now the pros to B&B trees is that there's much more selection and that you can plant pretty much all season except for birches that need to be planted in the spring. Oaks are best planted in the spring as well. But they are larger trees as well, which can be a good thing or a bad thing depending if it's you and your back that have to move it. 

They are very heavy, of course, and certainly they're more expensive, and it isn't easy when you're looking at the tree in the nursery necessarily to find that root flare. Also, I tell people that if they have a choice in balled and burlap between say a two inch tree and a four inch tree, and what I mean by a two inch or four inch tree is that these are measured by caliper or the girth of the tree. So you're looking at the girth of that trunk, and it's measured 4.5 feet up from the ground so you may see something that says it's a 1.5 inch caliper tree. That's where they measure that. And the thing is that the bigger the tree is, the more transplant shock it's going to undergo. So if you have a bigger tree, it's going to actually take a few years to catch up. For a few years, you're going to have small leaves, not much growth and then it will finally get established and catch up. But a smaller tree actually is going to catch up faster and may actually outgrow the other tree before it catches up so sometimes immediate gratification is not necessarily what you want to do. Okay, the other thing about balled and burlapped is that at least 50% of the plant's roots have been removed in the balling process. And in nurseries, what they do to make up for that and what they do is they'll grow the trees in rows in the ground and then before they sell them, they dig them up and they ball them. 

And the burlap wall sometimes is encased in a wire basket. We'll talk more about that in a minute. But in the process of doing the balling, sometimes the root flare gets buried, and an "old school" hole like this is sometimes referred to in the trade as a tree tomb. It's similar to the little holes that they make in the sidewalks in real urban areas because we know that the tree doesn't have enough time to-- or enough room for its roots to expand, and it typically will not last as long as a tree that has significantly more root zone available.

So what you got to do is you got to find that root flare. This involves some digging. Usually, I will find the root flare first before I even dig the hole because I don't know how deep to make the hole because I don't know how deep the root system is until I find the root flare. So you take off the rope. You pull back the burlap, and you start digging. It does mean you may end up cutting some roots, but you can see in this picture that probably a good six to eight inches of extra soil was piled on top of that root flare, and that it's really important to unbury that. 

The nice thing is that after you've done that excavation, you have a shorter hole to dig so you're actually saving yourself some labor there. And let me go back a second. That wire basket that's on the picture in the left, that has to come off. I don't care whether you leave it in order to get the tree into the hole, but as soon as it is in the hole, you need to take the thing off, and I'll show you a picture of why that is later. Leaving the burlap on, not a great idea. You can see that it's supposed to decay. However, it didn't in this case, and it can act as a wick. You can see it's kind of girdling the trunk, but it also can wick moisture away from the root system. And this tree was typically, as you can see, planted too deep because what's it got? Girdling roots going around the

trunk. That's what it looks like when you don't remove the wire basket. A lot of places will tell you that, "Oh yes, the wire is going to rust away." Not soon enough. It looks like in this particular picture that they also used polypropylene rope at the top, which some companies do, so that it doesn't rot before the tree is sold, but if the person who's planting doesn't know to take that rope off, that's a good girdling mechanism right there in itself. But you can see that this tree eventually had to be removed because the root system got gnarled up in the wire basket.

Then containerized trees. Sometimes these are the most challenging because you don't know whether that tree has been sitting in the nursery for one season or two seasons or more. And many times when you get it, it's got circling roots. It's trying to get out of that container, and circling roots can be just as bad as girdling roots and sometimes they can turn into girdling roots. 

So it's important to not only find the root flare but also if there are circling roots to straighten those out. And that is really the major drawback of containerized trees. Containerized-- I must say are my favorite because I don't like moving those big heavy burlap balls, and usually the containers are easier for me to move. Usually there's a good selection. They're cheaper then balled and burlapped. But they do have this very significant issue. So that's just something to keep in mind.

So here's an example of a containerized tree. Notice that the roots are really dense, that they have grown out and that they are doing some circling. So in trying to find that root flare, you have to actually get rid of a lot of roots. 

And you can see that the root flare is actually way at the bottom of the root mass, and they've had to remove quite a few roots. I know this looks really brutal, and it is. What I like to do is I do something like this actually in a wheel barrel full of water so that while I'm ripping roots away, I can at least keep the thing hydrated. But once you find-- the thing is if you left all those roots on, you're going to have girdling roots, and you're going to have big problems.

Okay, so now we'll talk about how to properly dig the hole. So the hole should be three to five times the width of the root system only as deep as the root system. You want to make sure that that root flare is either at or about an inch on top of the-- or above the soil grade, leaving the bottom of the hole undisturbed. You don't want to be putting any peat moss or compost or other stuff like that in there. What tends to happen when you amend the soil is that you-- particularly if you're in heavy clay, you get kind of a bathtub effect where if you've added a whole bunch of nice soil and the soil surrounding that is pretty crummy, the tree's root systm is going to say, "I ain't going out there. Forget it. 

I'm just going to stay in here and go around, around and around," and then you don't get good establishment, and you have a structurally unsound system going on there. So when I'm planting a tree after I have removed wire and burlap if it's balled and burlap or in any case found the root flare is I will orient the tree and either have somebody hold it or hang onto it so that it's straight, and then I will start refilling the hole. I put in about a third of the soil, making sure that if its bare root that I'm getting soil underneath those roots so we don't have air pockets. And then I will water it. Let the water sift down in there and finally go away. Then I'll add some more soil and repeat the watering. This is so that I am sure that I don't have a lot of air pockets in there.

And when you finally do get it, put in the ground, I will usually take some leftover soil and I'll build a little dyke or a moat or saucer you could call it of soil around the base of the tree usually about a foot out from the trunk, and that's sort of to be a water retention area so that when I'm watering it that I can fill that up with water, and it won't just run off, particularly if you're planting on the slope, it's a good idea to have the wall a little bit bigger on the downfacing side of the slope. Now for the first couple of years in terms of water, you want to make sure it gets one to two inches a week. So if mother nature doesn't provide, then it's up to you. 

You're out there with your watering can or your five gallon bucket or your hose. And usually I recommend hand watering. I think that's a lot easier than using a sprinkler. The sprinkler throws a lot of moisture into the air that the tree never sees. So I do recommend using a hose.

Some other things to think about, staking. Now, if we go back you can see that this tree was staked. Usually for shade trees, we don't recommend staking unless you need it. If it's a bare root tree, obviously because it has no stability whatsoever, yes indeed. Do stake it. 

And we recommend two opposing stakes on either side. You don't want to run it through the root ball. But fairly close to the tree, and there are specific products that we recommend. This is not one of them. Using a hose like this, you can see they moved it off the place where it was originally attached to the tree, and you could see it girdled the trunk. Also we only recommend that stakes stay on the tree for the first season or so. If you stake too tightly, you may end up girdling the tree. You sure don't want to use wire. But they do sell in a lot of the garden centers a product that is a canvas tie that has grommets in it. And it's very wide, and flat, and that's not going to damage the bark. 

So what you do is you loop the tie around the trunk and then you can use wire to attach through the grommet the tie to the fence post. And you do the same on the other side, and you want to stake somewhat loosely because if the tree doesn't have any movement to it, the trunk actually doesn't develop as much caliper as it could and caliper is really important in the stability of the tree. So you want it to get girth that it puts on, and so it needs to be able to shift around a little bit in order to do that.

Here's an artist conception of what that might look like and what those canvas belts look like.

This is another thing. Sometimes people will bring the tree home, plant the tree and leave the wrap on. The wrap actually isn't there to protect it from rabbits or voles. It's actually there just to protect it from damage while you're moving it and transplanting it. So it should be removed because you can see what happens when you leave it on. Again, you get girdled bark. 

If you do want to protect the tree over the winter, and I highly recommend this especially with new young trees particularly fruit trees because they are very tasty to voles and rabbits over the winter and one of the things I really hate is getting calls in the spring from people who say, "All my bark is missing from the bottom of my tree because a rabbit ate it. Is it going to be okay?" And remember what we said about the vascular system? It's right underneath the bark, so if the bark is gone, the vascular system is gone. The tree has no way to take up water. So then I have to go into grief counselor mode and talk to them about, "Yes, I'm sorry to tell you that your tree is toast and that you should do this, that and the other thing to protect it in the future."

We used to tell people back when I was an undergraduate to do a little bit of pruning at the time of planting. We no longer recommend that. Studies have shown that the tree at the time of planting actually needs as much photosynthetic material, i.e. leaves, as it can get at that time because that's going to support the roots. 

The old thinking was, "Oh, the roots can't support the leaves," so we've kind of changed that over time. You don't-- also we used to recommend putting fertilizer packets in the hole, and we found that the trees actually do better without the fertilizer at least for the first year. Generally trees don't need a whole lot of fertilizer, but-- particularly not at the time of planting. So the only thing that you would remove at the time of planting with your pruning shears is a broken branch or a broken root.

Mulching-- you probably noticed that the picture of the guy watering the tree, he had a good layer of mulch on there and mulch is good. That's a motto. Mulch is good, but it has to be properly applied. Like any good thing, it is possible to do it the wrong way or to do it too much. But the benefits of mulch include keeping the soil and the roots cool. It prevents large drops in temperature or rises in temperature. 

It helps especially if you're using an organic mulch such as shredded bark mulch to improve the physical fertility of the soil. So it will add organic matter to the soil and provide nutrients for the tree. It also helps keep the soil loose and allows macro organisms like earth worms to move around. Prevents erosion, another good thing. And it also is much better than grass. One thing that is a problem about having grass under trees, particularly things like birches, is that turf has very shallow roots, very thirsty roots too, and turf competes very well with tree roots unfortunately. So sometimes that adds an extra stress to the trees. And one of the things that I like to say is that mulch is a good barrier to having what we call mower blight, which means the mower smacking into the trunk. And I can guarantee that if you look around at some of the trees that are planted in the tree terraces next to the curb, you are going to see some good cases of mower blight if the tree has not been mulched properly. Also a good way to recycle some yard waste and it provides good environment for soil microbes that keep the soil healthy.

So, we have here a very sad example of inorganic mulch. I'm not sure what the point was of that unless it was to keep the mower away from the trunk because it's not adding any organic matter to the soil. There's not enough of it to be protecting the root system. So not real sure what the point of that exercise was, but you can see this list of different things that you can add as organic mulch. My favorite is shredded hard wood bark. The one problem with it is that sometimes it can become hydrophobic over time and start to allow water to run off. That's if it gets too dry. So what you would do then is just rake over it a little bit and help to roughen it up, and that should allow more moisture in. How much mulch to put in? A lot of people ask that question. 

It's a really good question. For trees, no more than four inches at the maximum. And it should not be piled up against the trunk. We've already talked about the root flare. If you put the root flare at the top of the soil only to bury it in mulch, you've achieved the same poor result as planting it too deep. So you want to have your mulch area go out at least two or three feet from the trunk and that will help the tree compete against grasses and other lawn sorts of plants. And usually you're going to need to replenish every other year or so. Now, here's what we call volcano mulching. This falls in the category of too much of a good thing, like way too much of a good thing. I have no idea what they were trying to achieve with the plant on the top. 

It looks like it's buried almost up to the first set of branches. We call it volcano mulching because it looks kind of like a volcano and the mulch is piled up against the trunk. And that can-- not only does it bury the root flare, but a lot of the trunk tissue especially in young trees is actually used for gas exchange, so oxygen exchange doesn't happen. And another thing that can happen is if you used what we call sour mulch, and usually I only see sour mulch occurring during really hot, dry summers. If the mulch that you purchased was piled up more than about four or five feet at the nursery, the interior starts to become anaerobic, and it starts to have decay happening that lets off things like methane and ammonia and so often we see if people are spreading that bark on beds where they have annuals that the annuals wilt and die. It can also effect the trunk of the tree and basically burn the tree. So, making sure that the mulch is in good condition is a good idea. Soil temperature issues applying at the wrong time. If it's hot and dry and then you put hot, dry mulch on top of it, you're not achieving the goal of water retention. So if it's hot and dry when you want to mulch, water first so that the soil is moist and then your mulch will do the job of holding that moisture in.

Here's an example of a tree that was planted correctly on Mike's left side. This is Mike Maddox, the master gardener state office program director, and the one on his right was not planted properly, and you can see there is quite a difference in terms of not only height but growth quality. The tree on the left side of your screen is dark green. It's tall. It's well branched. The color is good, and the other tree you can see it has poor color, not very much growth. And that's after just one growing season. And you can also see the tree on the right is having to compete with tree roots or with grass roots as well. Not mulched. So here's the summary then. 

Here's your take home message. Find the root flare of the tree when you're planting. Make sure that the hole is three to five times wider than the roots but no deeper than the bottom of the root ball. Align the tree in the hole as desired. Make sure that you only prune broken roots or branches. You don't do any other pruning. And you back fill with native soil. You don't add any soil amendments. Usually when you're planting, you want to water in several times making sure there aren't any air pockets. If you need to stake, you only stake for one season and then water and mulch appropriately. 

If you do have questions, you can contact me at the Dane County Extension office, and I will be happy to talk to you or have one of the master gardeners answer your questions. Thanks very much. 
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