Episode 2540

- [Narrator] The emerald ash borer has been responsible for the loss of tens of millions of ash trees across the US. It has now reached Tennessee. Phillipe Chadwick talks with two experts to learn what homeowners can do. And Marty DeHart tackles the question of soil pH. What is it, and why is it important? Plus, we visit with Jeff Poppen to learn the benefits of deep plowing. Join us. Not a question of if, but when.

- Here in Tennessee, the emerald ash borers are increasingly becoming a huge problem locally and across the nation. So we're gonna talk to some experts about somethings you really need to know. So it's currently here, there's no denying this.

- There's no denying it. It's sweeping across the state, all the way from East Tennessee, and it's reached middle Tennessee into Davidson County. It was first detected in Davidson County couple of years ago in the northeastern part, and they're monitoring it. But the trend for the emerald ash borer is once it's detected, it takes a few years, and all of sudden you have a major outbreak. So we're probably within a year or two of seeing something pretty significant.

- [Phillipe] Wow, so once it's detected, it's a rapid increase.

- It kind of like a tidal wave, it has to build up a little in momentum, but once it gets going there's nothing that can stop it.

- So there really is nothing that we can do about it?

- Not about the pest itself, it's gonna happen. It's an invasive species from China that just did not co-evolve with the trees, the ash trees we have here. So the ash trees are pretty much left defenseless. And once the EAB gets a foothold, they normally just last a couple of years before dying.

- Well as far as catching up, what specifically can a homeowner do?

- Well, it's gotta be a collaborative effort working with the government, the private sector, and homeowners, and all kinds of folks, who really need to get their act together. But homeowners are a key. And I would say the number one thing, especially in areas that are impacted by the EAB, or that are going to be impacted, is that homeowners educate themselves on the emerald ash borer. There's a lot of good information online, websites, city extension, and all sorts of places. But if you've got an ash tree in your yard, you need to learn about this pest, and learn what's gonna happen to your tree, and then determine your options. Do you want to remove the tree now, when it's probably gonna be easier and less costly to do it, or do you want to find a significant ash, maybe you have one that's very special, and you want to invest some money, and plant some insecticides. There are some treatments there that can help you maintain a healthy ash tree, but that's about all your options, unless the tree dies, you definitely want to replace with another tree. But those are about all the options they have.

- [Phillipe] So one important thing is to, identification, make sure that you know that you're working with an ash tree. How does somebody know that they've got an ash tree?

- Once again, there's worlds of information on the web, various agencies. I would advise folks to tap into that. Maybe buy a book on tree identification. But real simply, ash trees have some distinctive features. This is actually the leaf of an ash tree, and these are leaflets. You want to look for leaflets that are shaped like this. And most ash species have between five and 11 leaflets. And the one on the tip is usually the biggest. And they are all generally pointed. The distinctive part about an ash tree, because there's a lot of other trees that have a compound leaves, is the arrangement of the leaflet. And I don't have another leaf here, but they are arranged opposite, what's called opposite of each other. So you can look at an ash tree, and if you see the leaflet is coming off of a stem opposite another one, then that's a pretty good clue, that narrows down that you have an ash tree. Now the reason this is important is there's other tree that have compound leaves that are arranged alternately, like the hickory. It doesn't send the leaflets opposite to each other, but they kind of are staggered like stair steps. And I want to really emphasize that, because you want to make sure that when you have somebody come by to take down what you think is an ash tree, it may be a hickory, which is fine. Make sure you have an ash tree. And there's a lot of out there for homeowners to really make that decision themselves, or to call for backup, to help them identify that tree.

- Sure, sure. So speaking of backing up a little bit. Tell me a little bit about the history of this problem. When did it start? Where did it start?

- Well, they're piecing information together to kind of figure out how it got here. They think they know where it started, in Detroit, Michigan. They believe it may have come in in the mid-90s on some shipping crates from China. But due to the characteristics and nature of EAB, it takes a while for it to really develop enough of population to show death, and dieback, and mortality of trees. Anyway, that happened in about 2001 or 2002, I believe.

- [Phillipe] Is when we identified the problem?

- Is when they first saw the dieback in ashes. They didn't know what it was. And it took them a little while to figure out that it was the emerald ash borer.

- And I mean, that's only roughly 25 years ago, and it spread across the country in 25 years.

- It has spread across the northeast, the Central Lake areas, down the eastern coast, as far as Tennessee, and to Georgia. And now it's kind of making its way in slow crawl, but a steady crawl towards the west.

- What's the fastest way it spread?

- We can blame ourselves for that. But the beetle, the borer itself, it only flies like half a mile from a tree. But the biggest cause, or vector, for the beetles' spread, has been through people buying saw wood, or cutting logs for firewood, for fires, and taking them across state lines to a campground, selling wood products that are made out of ash trees, and sending those. Even nursery stock. There was ash trees was sent before they really figured out what was going on.

- I'm here with Scott Johnson, here's a board certified master arborist. And so if you have a really nice ash tree in your yard, and it's something you do want to keep and maintain, what are some steps you can take to do that?

- Well, I think the first step is identifying whether you have a valuable ash tree in your yard. It's not really realistic to preserve every ash tree in your yard. Trees like this that add value to the property, trees in the front yard, or trees that are over patios, three that have some type of aesthetic appeal to the property, those would be ones that a homeowner might consider preserving at that point. If you have ash trees back on a back fence row, or multiple ash trees around a tree, a more specimen oak tree or maple tree, it might be better just to remove those trees, and let nature take its course. A tree like this that is a decent size, kind of a focal point in the front yard, there's some options for treatment preservation. The main thing a homeowner needs to be aware of though, it's a longterm commitment. Once they start trying to preserve these trees, the insecticide treatment needs to be administered every year, or every other year, with the current chemistry. So they need to decide whether the value of the tree outweighs the cost of the preservation. And there's a lot of good cost calculators online to help determine that. This particular tree, in general, what you do is you determine the diameter of the tree, then the amount of insecticide applied is determined by the diameter, inches of the trunk of the tree. There's several different options. The two most common are injecting the chemical into the soil, and it taken up systemically into the tree. That provides one year worth of protection, with the current chemistry. There's another option where you can inject the chemical directly into the trunk of the tree, and that can provide to your source of protection. But the homeowner, if they take on this responsibility and this task, they need to be aware that this is something that's gonna affect their budget, year after year.

- Sure, sure. When is the best time to do these treatments?

- Generally when the sap starts flowing in the spring. You can do them throughout the summer if needed. But the best time to do it is that early spring, once the sap starts flowing. Because both options are systemic, they're injected in the trunk, and taken up into the foliage of the tree. That way the entire tree system has the insecticide in it.

- Yeah, it has that protection.

- So what we know about the EAB, and how it spread across the country. These cities that have been infested before, the cities in middle Tennessee, all the ash trees that have been permanently treated in those cities have died. So we have a very short window. They say there's a mortality curve. And once the emerald ash borers have been detected, it takes four, five, six, years for the population to build. Once it hits that five, six, seven year window, that's when you start seeing mass-mortality of these emerald ash borer trees. It's unlikely that the tree will uproot and fall over, but a lot of the big scaffold branches will start to dry out, and start to fall down on personal property. So it's definitely something the property owners need to be aware of. Once you start having about 30% thinning up in the canopy, it's too late. The bugs starts attacking the tree, and the upper part, a lot of times, you can't even notice that the tree's been infected, infested with the bug. You start seeing the thinning up in the top of the canopy, and once it reaches that 30% mark, there's no going back, the homeowner is basically wasting their money if they try to preserve it at that point. Some of the symptoms to watch for, to see if your tree is infested, obviously that normal dieback up in the canopy. There are epicormic shoots or water sprouts that start growing on the trunk, where the tree is trying to produce this energy for itself. D-shaped emergent holes, where the bug actually comes out of the tree, and exits its life cycle within the tree. Also woodpecker damage. Wood peckers will get up in the canopy and try to munch of the larva during that life cycle.

- So a very important thing too, is making sure you get a certified arborist in your local area, that really knows what they're doing, so they can correctly identify what's going on, and make the correct steps. Absolutely, with the type of investment homeowners are gonna have to make to try to preserve these trees, and then make sure they have a reputable company that's on their side, somebody that is insured, bonded. Somebody that's been around for a while. In other parts of the country, some folks will chase this bug around, knowing that there's gonna be a lot of trees removals on the back side of an infestation. Make sure you're working with somebody that you trust, that's been in your community for a while. If they have a certified arborist on staff, even better.

- Well, some very good information on a scary thing that's happening in our area. I appreciate your time and your information, and I hope everybody takes these comments seriously, because it's everybody's backyard. It's here, and it's coming quickly, so thanks again.

- Thank you.

- We never water our gardens, yet produce bountiful and abundant crops year after year. How do we do this with no irrigation? The answer is in deep plowing and soil surface management. I collect and study grade school textbooks on agriculture, from before World War I. And they clearly explain the value of hummus, compost, cover crops, and other organic practices. But most importantly, they've taught me how to collect and keep the moisture in the soil. By thoroughly loosening the earth in the fall, the winter and spring rains soak in, and then are available during next summer's drought. This stored water rises to the surface by capillary action, much like the way water rises up this paper towel, when I dip it in the water. Farmer uses plows and subsoilers to loosen up the soil deeply. As gardeners, we'll use shovels, and forks, and picks. What we want to do is to move the top soil off to the depths of about, it's usually eight inches or so deep. Then you get to another layer of soil, that we call the subsoil. It will be lighter in color, and be generally more compacted. You can sort of see the transition between the top soil, this other layer, and then the clay subsoil. Here is the clay. I used to not like clay, because it's sticky and hard to work. But I've realized the importance of clay in moving soil moisture upward. To loosen up the soil beneath the top soil, we simply take a pick, and work the ground deeply, and we leave that subsoil down there though. We don't want to bring it to the surface because it's not very fertile. We just want to open it up and get air in it, so that the water that falls during the winter and spring, has a place to soak in, so that it can move back up later on by the capillary action. And now we'll put the soil back on top, after we've loosened up the subsoil. Clay has very fine soil grains, while sand has very coarse grains. The best soil is a mixture of both. In the tomato patch we use a hay mulch to keep the ground moist for the tomatoes. It also keeps the weeds down, and adds valuable organic matter. When you pull back the mulch, you can see that the ground underneath it stays good and moist. Now, I can't put hay over eight acres of vegetables. So in most of our gardens we use the old-timey method of cultivation, which leaves a layer of tilled earth on the soil, which is called a dust mulch. As soon after rain as I can, I get into the gardens, and hoe, rake, and cultivate the surface of the soil, so that I check evaporation. I want to keep that soil moisture in the ground, so that I have it there for the summertime when it gets real dry. Here, where we've cultivated yesterday, you can see where the soil has already dried out and formed this dust mulch. If I rake that away, you can see how moist it is underneath. This moisture will stay there, and won't leave the ground with the dry dust mulch on top of it. Never let your soil crust over or get hard. You want to keep that soil loose and fluffy all the time, so that your plant roots can get down in there, and get the nutrients it need, and move around easily. This makes for happy plants, healthy plants, and great tasting vegetables. Deep plowing in the fall has another advantage. Here in Tennessee, the winter weather alternates between freezing and thawing several times. And overturn chuck of soil will fill with water, which will then expand when it freezes. This pulverizes and softens the soil in a way that no mechanical tillage can do. With deep plowing and soil surface tillage, we can grow all the crops we want, just by using the moisture that mother nature provides throughout the whole year. Summer droughts are to be expected here in Tennessee. But with deep plowing and soil surface management, we can coax the underground moisture up, and water our plants during the dry spells.

- We're at a destination nursery today, and we're gonna show you what's a little bit different about this place. Not only do they grow the plant material, but they also show you how its gonna look in a couple of years in your own garden setting. I'm here at Bennett Nurseries, north-side of Huntsville, and I'm talking with Jeff Bennett. And Jeff, I want to talk a little bit about your vertical, about your accent planning, I guess, in your beds.

- Sure, sure. These beds, where we're standing, they've only been here for a couple years. But folks can get an idea of what they're going to see in the near future. For example, this evergreen here is a variety called Prairie Pillar. It is a juniper. It's an Eastern red cedar, an old-fashioned cedar tree. But what unique about this one is that would get to be about 15 feet tall, but only a couple of feet wide.

- [Sheri] And behind it is a nice grass.

- Behind it is a very good grass. We've just recently learned about this one. This is called Northwind, it is a type Panicum, Northwind switchgrass. And although it's quite vertical and upright in the summertime, it's unique, in that in the winter, it turns a copper color, and does not fall all over the landscape, maintains it fertile.

- Not only do you have shrubs, you also have some flowers. And I noticed the type of yarrow here. Tell me about some of the other things.

- Sure. We're trying to incorporate, not only the permanent plants, of course the perennial, this yarrow here is Pink Grapefruit, and then some annuals at the base of it. We've got some more focal points in this bed. This is Verdoni Chamaecyparis right here, nice golden. And a Dwarf Chamaecyparis. Back behind it is another vertical Japanese maple here. That's called Tsukasa Silhouette, very upright green leaf, narrowing growing Japanese maple. This little Japanese maple has really gained a lot of attention for us. It's called Mikawa Yatsubusa. And a very tightly knit leaf structure to it. And then if you can see up on the trunk right there, its ribbed trunk, it looks like bamboo. It will be a dwarf as well, nice, good orange to golden fall color.

- [Sheri] Is this a Cypress?

- It is, it's a Bald Cypress. It's actually a Dwarf Balled Cypress, it's called Peve Minaret. And this Bald Cypress won't be enormous like some of the large specimens you might see down in the swampland. But it's maintaining the corner of this bed here with an underplanting. Mainly for the hummingbirds, this is a firecracker plant, Cuphea ignea. Another Cuphea in front. Just a hummingbird filling station here. Ended up with a Angelina Sedum on the edge right there.

- [Sheri] I know you have another bed up a little bit farther, so let's go take a look at that one as well. Gosh, tell me about this blue.

- Oh, this is one of those heat-tolerant Blue Lobelias here, it's really an electric color. We don't get a chance to see the Lobelia much in the south here, so this heat-tolerant blue, and there's also a white that we've been using for the past couple of years.

- [Sheri] Wouldn't that be fun to put red, white, and blue?

- [Jeff] It would be. Very patriotic. We got a little bit of red in here, but it's not showing just yet. Behind the rock we have an Encore Azalea, Russian Sage, and then Fernspray Cypress is peaking out above it.

- [Sheri] I like growth habit of that. Now tell me about what you said was your favorite thing in here.

- Yeah, right at the back here is a new Japanese maple. Some folks are familiar with coral bark maple, a variety called Sangokaku. This is actually one called Bihou, and it is a yellow-barked coral bark maple. So in the wintertime we'll have some very nice fall color, golden to orange, but then the foliage will fall off and reveal a very yellow to orange bark to it. Really nice in this bed for the wintertime.

- [Sheri] I think it goes nicely with all the chartreuse that people are seeking now in their gardens as well.

- Certainly just like the Creeping Jenny at the base of it right there, really highlights the bark. But this is just one example of one of the many things that we try to carry here. We're not just your average garden center as far as a few vegetables and bedding plants. We really try to have not just your basics, but something unusual, something new. You've been doing gardening for many years, and it would be no fun if you couldn't try the unique and the unusual. So we try to showcase it in our own beds, as well as offer it, and give advice to the customers that come by, want some help, "What do I do? "How do I do it?"

- [Sheri] Well, thank you so much, Jeff, it's been great. You introduced me to a lot of new and different plant materials.

- We are here today, and I'm really happy to be here in Nashville, at Ellington Agricultural Experiment Station with Debbie Joines, who is the manager of the, say it for me.

- Soil plant and pest center.

- All right, this is where you come, this is the UT extension place, where if you've got a problem with anything, and you send it in to the UT extension, comes to her, her outfit, and they check it out. And she is the pH queen. We are going to talk about what it is, and why pH is so important in gardening. And people know that it is, but they don't quite know why. And maybe you can explain that.

- Well, essentially, the importance of pH comes with availability of plant nutrients. So you can fertilize, or you can add compost, and so forth, but if the pH is not correct in your soil, the availability of those nutrients to your plants will not be there. So what we like is a slightly acidic soil, around 6.5 pH, with seven being basic, 7.0.

- [Marty] It goes from zero to 14, theoretically, right? But where's the zero and where's the 14?

- Yeah, it's way--

- Yeah, the moon, maybe.

- That's right. But 6.5 is what we're after. And our soil test recommendations are that we recommend lime, if the pH drops to 6.0 or below. And the reason being, once that pH gets down in the low fives, or mid fives, the primary plant nutrients that the plants really like in great amounts become unavailable to the plant.

- [Marty] Now there is an exception though, a group of plants that likes that acid, right?

- Yeah, we've got azaleas, rhododendrons, blueberries like an acidic pH.

- [Marty] They're all members of the same big family.

- That's right. They like a pH stand around 4.8 to 5.2. There is some talk that some potatoes like a little bit of acidic soil. Not down in the low fives, but less than six.

- Well, I know growing potatoes on very alkaline soil, you get all kinds of problems.

- Yeah, sometimes you can run into disease problems, and so forth.

- Scab.

- Yeah. So that pH is very important. Be aware of wood ashes. I do a lot of tests for folks that apply wood ashes on their gardens.

- Right, from their fireplace.

- I did it myself when I started having problems, and I thought, "Okay, Deb, you need to pull a soil test." And I did, and my pH was up to high. It was up almost eight. And so I had to apply sulfur to lower that pH back down. These are some soil samples that were sent to us this week.

- [Marty] Look at the range in colors.

- [Debbie] Uh-huh, they're all different colors. The great thing about these soil samples, is the folks send in plenty. We do need a full box of soil, and the reason being is that we recommend a six-inch sample, and that's a sample taken from the top through the six-inch depth. And if you just take one sample, it's not gonna fill up that box. If you've got a 2000, 3000 square foot garden, then you need several samples, and mix those together.

- [Marty] 'Cause the pH can vary across that span.

- [Debbie] Exactly.

- [Marty] And where do these boxes come from?

- [Debbie] You can get those boxes from your local extension office. We have an office in every county in the state, and you can pick up those boxes there.

- [Marty] And just take it, send it in?

- Mm-hmm, send it in.

- Awesome. You do what with these? You grind it up and--

- Yeah we grind, first of all, they're dried. And I don't recommend out viewers to dry them at home, because you can affect the results by drying them inaccurately.

- Just dig it up, and send it as you dig it.

- If it's terribly wet, put it out on a paper plate, let it dry overnight. You send the samples to us, and we do grind those up into finer particles, so that we can measure them out, and do a good job scientifically on the test.

- And then you test it, and you run all the specs, and what does the person get back?

- They get a report back that has all the recommendations, the lime recommendations, and fertilizer recommendations. They can use those either organic or inorganic, call it whatever they want, and we'll tell them how much to apply in 1000 square feet.

- Fantastic. Okay, so now, just as an example, I mean, everybody, especially around Nashville, people try to grow azaleas, for example, and often run into difficulty, chlorosis, which is where the leaves get yellow, and their veins may still be green, but the plant just looks kind of sickly, and then the lice bugs eatit. That chlorosis is what?

- Essentially, it is a deficiency that's caused by high pH.

- There you go.

- Notoriously we see samples in here from homeowners who have azaleas dying, they've planted them, they've died, they've planted, they've died again. And then they pull a soil sample. Well, what typically that is, is a high pH. And what we'll recommend is sulfur to lower that pH.

- Sulfur?

- Uh-huh. And what happens is, iron is only available at lower pHs, around 5.5--

- So it maybe in the soil, but the plant can't get it, because the pH is too high. How 'bout that? So you say put elemental sulfur down, and water it in--

- Yeah, water it in, mix it in real well, and remember--

- Now, what if you've got big established plants though, and you can't dig the soil up, 'cause the roots.

- Yeah, I would probably recommend aluminum sulfate, or something like that. It doesn't have as much sulfur in it. We're still lowering the pH, but we're doing it gently. Little bit at a time.

- That's softer way to do it than the elemental sulfur.

- Yeah, you don't want to shock the plant to great. But we're still accomplishing the same thing, it's just gonna be a little slower. And just remember, any time your changing the pH up or down, it takes time.

- No matter what you're growing. It's a good idea to know what it is you're growing in, what's your soil made up of, and how is it going to react, and what are you gonna have success with, and what are you not, and are you willing to change it? I mean, if you love rhododendrons, you're gonna make the effort. Well, this is fascinating stuff. We don't think about green thumbs as being a chemistry project. But actually--

- [Debbie] It is.

- [Narrator] For inspiring garden tours, growing tips, and garden projects, visit our website at volunteergardener.org, or on YouTube at the Volunteer Gardener channel. And like us on Facebook.