Dan Blazer from Davey's Southwest Milwaukee office shares six salt tolerant trees that are a good idea to plant near roadways, as well as which trees he does not recommended planting near roadways where there is heavy salt traffic. Dan talks about how you can start preparing for winter now by getting these trees planted this fall.
In this episode we cover:
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To learn more about protecting your trees from salt, read our blog, How to Protect Trees from Winter Salt or Rock Salt Damage.
To learn about how rock salt may be affecting your property, read our blog, How Rock Salt May be Affecting Your Lawn.
To learn more about emerald ash borer (EAB), read our EAB blogs.
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Doug Oster: Welcome to the Davey Tree Expert Company's Podcast, Talking Trees. I'm your host, Doug Oster, each episode showcases one of Davey's certified arborists sharing advice with everyone about caring for your trees and landscapes. We'll talk about everything from introduced pests, seasonal tree care, dear damage, how to make your trees thrive, and much, much more. Tune in every Thursday to learn more because here at the Talking Trees podcast, we know trees are the answer.
This week, I'm joined by Dan Blazer, a consulting arborist for the Davey Tree Expert Company located in New Berlin, Wisconsin. How you doing, Dan?
Dan Blazer: I'm doing great. It's a beautiful fall day up here in Wisconsin.
Doug Oster: The same here. We had a cold front through yesterday and it definitely feels like fall today. We're going to talk about a pretty important topic right now, salt-tolerant trees. A lot of times when we're thinking about planting, as we're cooling off as this is prime planting season, but there are some areas where if you're close to the road, close to the sidewalk, I wonder what you thought about that, should I be looking at a tree that can take the salt or should I be looking at it from another standpoint where I'm just figuring out something else to put down close to that tree that's not going to hurt it, or we go both ways there?
Dan Blazer: Absolutely. Site selection, we consider a lot of things when we're planting trees but the planting site and the soil conditions and proximity to roadways, roadways and parking lots, and stuff that receive salt is of course of consideration. There are several trees that we like to use in those locations that can tolerate drought, salt, heavy clay soil, and what we call poor soil conditions.
Doug Oster: If you do need to put something out there by the road that's going to get salt, what would be the first couple trees that you would think about putting there?
Dan Blazer: The first ones that come to mind would be the hybrid elms, Dutch elm disease-resistant varieties of American elms that they've cultivated over the years. One is called Princeton, and the other is known as the Triumph variety of hybrid elm, very salt-tolerant. Back before Dutch elm disease, American elms made such wonderful street trees because of their tolerance to the urban soil. Unfortunately, Dutch elm disease took those out, but your good hybrid elms are great. Another one that comes to mind is Kentucky coffeetree.
Doug Oster: Tell me about the Kentucky coffeetree because I don't know a lot about it.
Dan Blazer: Kentucky coffeetree is in the legume family, so like your honey locust or black locust, they have leaflets with a main leaf stock so the leaf contains multiple leaflets native to middle America, Upper Mississippi Valley, Ozark Plateau, and are probably found native as far north as Southern Illinois. Well, in Kentucky, of course.
Doug Oster: [laughs]
Dan Blazer: They have a honey locust appearance. They're dainty at first. They're very stick-like looking from the beginning but they become very beautiful trees. They're not a very fast-growing tree but they are in it for the long haul because-- there's some beautiful specimens that are 75 to a 100 years old here in the Milwaukee area that just are beautiful, they don't get too huge, which is also great in an area near a road, you don't want trees getting too huge either.
Doug Oster: Is it just their genetic makeup that over the years, arborists have figured out like, "Okay, this one, this one, this one," just the salt doesn't bother 'em as much as other trees.
Dan Blazer: Yes. That's one that I can't answer. There's a lot of unknowns that go on in arboriculture or any science, all we can do is do what we know works based on trial and error.
Doug Oster: After the Kentucky coffee tree, is there anything else you thinking of that would be a good choice?
Dan Blazer: Absolutely. If you're looking for a maple, everybody loves their maple. Everybody loves fall color. Our native maples, not so tolerant to urban soil. They're pretty tolerant but not extremely but the Miyabe maple, also known as the State Street Maple, is a great combination of all the wonderful features in a maple that you could ask for. They do get a nice reddish fall color. They're a medium, they have a medium growth rate and they're also very tolerant to drought and tolerant to salt. They're one of the better, most underrated maples that they're not utilized as much yet as I think they should be.
Doug Oster: I talked to a lot of arborists that one has never come up. That's really interesting. How big does it get eventually when it's mature?
Dan Blazer: Oh, there's a specimen at the Chicago Botanic Garden that is gigantic. They can get pretty, pretty big, at least as good as size as a sugar maple. Being introduced here, they've only been planted for such a long time so I guess we don't really know how long or well they're going to do here, but the ones I've seen so far, so good.
Doug Oster: What else is on your list?
Dan Blazer: Yes. Ginkgo Biloba, you see them a lot in boulevards. They're really a miracle tree. They're prehistoric in the fossil record. There's not many plants or trees that are found prehistoric in the fossil record so they did live through. They're older than the dinosaurs, basically, and not many trees are, so they stood the test of time. They don't have any real native or exotic pests that attack 'em.
Doug Oster: Gold fall color too, right?
Dan Blazer: Yes. A nice gold fall color, absolutely. They're very pretty slow-growing tree.
Doug Oster: You don't want one of the-- what is it? males or females? what makes the fruit that everybody complains about?
Dan Blazer: Oh, yes, the males. Generally not around anymore in nursery stock. That's an older thing but every once in a while, one's pop up in the nursery and they don't know how but they show up and they might not produce fruit for 15 or 20 years after they're planted. You might not know you have one until all of a sudden you get a bunch of these red awful smelling things falling all over the place.
Doug Oster: Then you'll know, right?
Dan Blazer: Yes. Next tree, if you want to know a couple more, honey locusts are also a great urban tree. We don't use a lot of those because we want diversity in the urban forest as a whole. We don't want to have more than 10% of any given species for resilience as a whole.
Doug Oster: You have a lot of honey locusts planted all around the city, right?
Dan Blazer: Absolutely. We don't use a whole lot of those because they're in general, there's a lot of those already around.
Doug Oster: Makes good sense.
Dan Blazer: Yes.
Doug Oster: I grew up with one in the yard and so I have a special affection to him, but it's so important, again, talking to arborous, diversity is so important when you talked about those elm trees before Dutch elm disease, the roads were lined with elm trees before that we go back to chestnuts. Always planting something different and I hadn't heard the 10% rule. That's a great one.
Dan Blazer: Yes. If you want to go over the mistakes that have been made in urban forestry over the years, the chestnut thing, absolutely, both native and ones planted.
Doug Oster: Actually, ash here in our area, ashes are completely been wiped out.
Dan Blazer: Oh, my goodness. Absolutely. When the elms got knocked out, a lot of the urban trees were replaced with Norway maple, honey locust, and primarily, green and white ash. With emerald ash borer, I want to say 99% of our ash are either declining or already gone.
Doug Oster: Yes. I hear they're mostly gone. Do you guys have any sense of if the ash might come back just sprouting from below and hoping that the pest has just move on to that fresh new ash forest, or is it too early to even tell if we would get our ashes back?
Dan: A lot of scientists are talking about this. What I think is a lot of native trees are actually going to grow back but the emerald ash borer is still going to be around. Ash tend to need to be a certain diameter before they really become infested. I'm seeing a lot of regrowth of ash, when the trees died, they would sprout back a lot of times from the trunk.
In wild areas, I'm seeing lots of small ash. In fact, even on my own property, I have ash trees, both green and white, between two and four-inch diameter that are still alive. There is going to be a food source for emerald ash borer in wild areas. These urban trees that are on the treatment program are going to need to be treated I think for the rest of my career as an arborist.
I think it's purely speculation, anything can happen but I think that they're not going to go away. They will naturalize a little bit which means their population is going to go way, way way down because they've had so much food, they've been able to reproduce at such an exponential rate. EAB in ash trees, if you're treating your ash and your ashes are still looking good, stay on that two-year treatment plan with the emamectin benzoate, two-year trunk injection treatment, that's going to be required.
Doug: The only thing that's going to save them.
Doug: Anything else on your list before we move on to a couple of other topics?
Dan: Well, I didn't talk about the oak. We talked about the elms and the maples, I don't want to leave the oak out of the question. The swamp white oak. There's also a hybridized oak that is a cross between swamp white and bur oak which is called the Schuetti oak, S-C-H-U-E-T-T-I. These trees, both the swamp white and the hybrid, the Schuetti are very resistant to salt. You do see these oaks on boulevards. They are native, swamp white oaks are native here in Wisconsin. To be able to use a native species of tree in the streets is good as well.
Doug: How about things not to plant near areas that are going to get a lot of salt? Are there certain trees that are just like, "Don't put that one out there, man, because it hates salt"?
Dan: Absolutely. That is going to be basically any conifer, they don't like the salt, they don't like salt in the water and the root system. They also don't like salt spray on their foliage. White pine, probably the absolute worst to any kind of contaminated environment. Even drainage, conifers have to have adequate drainage at all times and absolutely no salt.
Doug: Tell me a little bit about how you got into this. Why is this job right for you?
Dan: Arborist? It is right for me. I have been an outdoorsman since I was a little kid and to be able to find a job that fits my personality and loving the outdoors, it's a huge bonus. I guess I'd like to say this job found me. It was just like, "Tree work, arborist?" "Absolutely, that sounds fun." Of course, after a while it becomes work but--
Doug: [laughs] Yes, everything does.
Dan: Tree work is hard, hard work.
Doug: Well, since it is such hard, hard work. Why is it right for you?
Dan: Well, I like physical activity, I like sports. You have to be a strong soul to be working out in the cold in the winters and to go through it.
Doug: It takes a certain type of person to want to be out there looking up at a tree when it's 2 degrees, right?
Dan: Absolutely. There's a lot of people out there that it's a great job for and they find the career and they stick with it.
Doug: How about a few of your favorite trees, now we're getting to planting season. Let's forget about the salt for a little bit. I certainly know from doing this podcast, it's all dependent on the site but is there anything in your mind when you start thinking things that are underused or things that you love that it's exciting for you when you can get 'em into a property?
Dan: Yes, there is. Some of the trees that I really, really love tend to be the more rare, or maybe they might be a little bit of fussy plants. I love Canadian hemlock, I just love their dark green foliage. They remind me of going up north when I was a kid because we have a number of hemlocks near the property. I've always loved them. I tried to grow 'em here, they don't do very well in our clay soil in southern Wisconsin. I think they like a little bit more acid and a little bit better drainage. I think a little bit-- a cooler growing season.
Doug: Here in Pennsylvania, we're under attack. Hemlocks are a big part of our forest and we're under attack by hemlock woolly adelgid. My property in particular probably has-- I would guess 50, maybe a 100 hemlocks. I'm working on it but that's a lot of trees to have to treat. That's an interesting choice for you. Have you had much success at all, like you said, in trying to get those hemlocks to do their thing?
Dan: I've had the ones that I have on my property, I have about five of them I planted about five years ago. They put on new growth every year so I'm keeping 'em alive. I've amended the soil around them with sand and peat moss to help with drainage and have a little bit kind of a more loamy soil structure to help decrease the soil pH because where I live, the soil pH is extremely high, very alkaline.
Doug: There's something about people that love plants, that they always want to grow something that isn't exactly right for their area, whether it's a hemlock for you or fig tree for me, whatever it might be.
Dan: You know what I have right next to my hemlocks? Some rhododendron.
Dan: Acid-loving flowering shrubs, that they can't get too wet, they can't get too dry, they can't get too much sun. Broadleaf evergreens are one of the fussiest plants because they have their foliage all winter. If we have harsh winters which we have harsh winters every single year, they curl up, they don't look good. Yes, the fussy plants.
Doug: Here in our climate, they are the stars of the garden about the third week of May. I don't know when they would bloom for you guys, maybe a little later or around that time?
Dan: These last-- I want to say five years, have been pretty different from one another. We've had some pretty early springs and some pretty late springs but right around then yes, is when I would have them about May 15th or the last week in May.
Doug: All right, Dan, I'm going to leave it right there. That's good stuff, especially for all of us that live with the impending doom of snow and salt on its way. Appreciate your time and the information. Thanks again.
Dan: Thank you. Take care.
Doug: I don't know about you, but I'm not looking forward to winter at all. Tune in every Thursday, the Talking Trees Podcast from the Davey Tree Expert company. I'm your host, Doug Oster. Do me a favor, subscribe to the podcast, we're having so much fun here. Next week, we've got planting secrets from an arborist, and the answer to the question, why doesn't my hydrangea bloom? That is the number one gardening question. As always, we'd like to remind you on the Talking Trees Podcast, trees are the answer.
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