Should You be Watering in the Winter?

Michael Sundberg from Davey's South East Denver office shares how he handles winter watering in Colorado's (typically) year-round dry conditions.

In this episode we cover:  

• Winter in Colorado (1:17)
• Watering in all four seasons (3:55)
• Handing faucets in winter (4:47)
• How arborists water client trees (5:15), (12:37)
• How to know how much to water (8:19)
• How weather impacts arborists' work (9:35)
• Problems caused by moisture levels (10:30)
• Importance of watering (13:30)
• Soil conditions in Colorado (14:52)
• How trees are chosen in Colorado (16:15)
• Fertilization (17:20)
• What Michael likes to plant (18:13)

To find your local Davey office, check out our find a local office page to search by zip code.  

To learn more about watering in the winter, check out our blog, 'What You Need to Know about Watering Trees in Winter (Even in Colorado!)'.

To learn more about caring for trees in the winter, check out our blog, 'Tree Care Checklist: How to Keep Trees Healthy This Winter'.

Connect with Davey Tree on social media:
Twitter: @DaveyTree
Facebook: @DaveyTree
Instagram: @daveytree
YouTube: The Davey Tree Expert Company
LinkedIn: The Davey Tree Expert Company 

Connect with Doug Oster at www.dougoster.com. 

Have topics you'd like us to cover on the podcast? Email us at podcasts@davey.com. We want to hear from you!

Transcript

[music]

Doug Oster: Welcome to the Davey Tree Expert Company's podcast, Talking Trees. I'm your host, Doug Oster. Each week, our expert arborists share advice on seasonal tree care, how to make your trees thrive, arborists' favorite trees, and much, much more. Tune in every Thursday to learn more because here at the Talking Trees podcast, we know trees are the answer. I'm joined again this week by Michael Sundberg. He is a district manager for the Davey Tree Expert Company in the Southeast Denver, Colorado, area. Today, we're talking all about winter watering, and Michael, watering in the winter? I've never heard of such a thing.

Michael Sundberg: Yes, it's a crazy thought for some parts of the country that get too much snow and get buried for the whole winter, and yes, a whole different climate out here in Colorado because we're sort of a high plains desert. We do have winter. We have great skiing in the mountains, but down in the front range where a lot of the trees we care for are located, we will have tons of stretches without snow for weeks, and sun's out most days. You get wind, all the different factors that dry out our trees. We have lots of winter watering that we have to factor in for our tree care compared to other parts of the world.

Doug: Tell me a little bit more about that winter season for you. I think we have a misconception in the East that you guys have snow all the time. Every spring, we see some story like on Mother's Day where Denver has 22 inches of snow or something, but what is the winter really like? When does it start, and how long does it last?

Michael: Yes, the crazy thing about our weather is we can get snowstorms in October through May. We've had some of those crazy Mother's Day snowstorms, but generally speaking, temperature-wise, Thanksgiving, we cool off and we stay a little bit cooler into the February, March season. We get a lot of our snow in March, so that's one of our snowier months. October, November, December can be pretty dry. We don't have a ton of Christmas days with snow. That's the exception compared to the rule for us. We get snow randomly, and we don't get buried in snow for very long either.

Because the sun's usually out, we end up getting snowstorms, and then the sun melts away the snow, and we're back to dry pretty quickly. Winter for us is pretty quick. Yesterday was 71 at the airport, so that's how unusual the weather can be where you get different seasons throughout winter still, and then we'll still have our winter days where the highs are below freezing, and you get snow for a day or two, but ultimately, it's a flash in the pan as compared to our other seasons. Some years we joke that there's summer, fall, second summer, second fall, third summer, winter, spring, and then we carry on.

Doug: Does the ground ever freeze solid?

Michael: Occasionally, especially if you get enough moisture on the front end, where it gets cold enough and there's the water to freeze up the soil, but for us, we can do tree watering and tree fertilization where we're probing into the ground. Year-round, we don't have a lot of winter days that we truly can't get the device in the ground, aside from maybe a week here or there. The ground doesn't get permafrost, especially because the sun's out so often, so that just cooks things pretty quickly for us.

Doug: Yes, so out east here, we water up until that ground freezes, which used to be November, now maybe January, maybe February, depending on the winter. For you guys, that means constant watering just as you would in any other season?

Michael: Yes, and the challenge is just that the sprinkler systems have to get winterized because it does get too cold for the backflow device and you can get some frozen irrigation pipes in the soil if it's buried not deep enough, that kind thing. Once I would say October rolls through, most people have winterized their sprinkler systems and you'll still have dry soils all the way till they pressure up the system again with the exception of some Marches where we get plenty of snow, or we get a big dump that lasts for a while. For tree care, I would say on about a monthly basis, we're doing winter waterings for people November through March to keep the soil moisture maintained. Otherwise, stuff just gets dusty dry, because we'll have stretches of, I don't know, three, four weeks without a substantial snowstorm sometimes.

Doug: For the home gardener, the home landscape, are the spigots shut off at a certain point as the sprinkler would be, or can you leave it on like for the home gardener?

Michael: Yes, most houses will have outdoor faucet, like the spigot off the house that you can hook up to in the winter. It's designed to not freeze after you use it. You do want to make sure you drain your hose and disconnect it from the house. That device is usually available for hooking up to do DIY watering.

Doug: For you guys, when you're taking care of clients, talk about how you water the trees.

Michael: For us taking care of clients, we'll bring a truck out with water. We'll have that water run through a pump. We actually get to put it down into the ground at a higher pressure than somebody that has a probe for their own hose. We can go 100, 150 PSI, which also helps with just sort of, I don't know, fluffing the soil in a way and decompacting it because you get some fracturing effect with the higher pressure that gets injected. Then the probe goes in four directions in the ground too. We can go in, we get below the turf grass layer, below the mulch layer, that water goes in under pressure. We're focusing on the root zone where the tree has the finer absorbing roots near the drip line of the canopy.

Then we're injecting the water that way. It's efficient because we're not losing stuff down to runoff going down the street if you did like a surface water, especially when the soils are dry, they don't even take water in very well on the surface. Yes, and that's the way that we bring water to the trees from a service standpoint. If people aren't able to do it themselves or have the time to do it, which is one of the other problems people have is they might spend hours doing their own trees because you're just doing a trickle versus us coming out as a service. We can do it pretty quick and people can enjoy their days instead of standing outside watering themselves.

Doug: Watering is one of my least favorite jobs because just standing there. I talk about it all the time where I leave the hose there, I let it run, I go do another garden job. For that probe, how deep does that go when you're watering or does it depend on the soil or does it depend on the roots? Does it depend on the tree?

Michael: For the device, you can go 6 to 12 inches. It just depends too on the soil factors. Some soils, it's easier to go further down than others. Also, the moisture levels will dictate how easy it is to probe in. I always say a good rule of thumb to check your soil moisture is just a long screwdriver and is it easy to push into the ground or not. When we come out to water, if it's been really dry, it might be harder to get as far down. If you're getting below the surface, you're at least getting that water where you need it because your roots are generally in the top foot of the soil. That's the area you're trying to maintain moisture best in

Doug: Let's say in the case of like a maple that's shallow rooted, are you going on the outside all around it or are there four spots or one spot or how do you decide that?

Michael: Yes, tree size will dictate that because of the size of the drip line. On a younger tree, if you're going every few feet where you're probing in, going around that drip line, some trees might have four spots and it's a four corners coverage of the drip line. Then you're going to get enough lateral coverage in the soil to get that root zone done. Then, larger tree might be going just every two, three feet, just going around the drip line and probing in a big circle to focus on those more finer absorbing roots.

Doug: Is there a formula or how do you know how much water to put on or do you just do the screwdriver test?

Michael: That's the great question. That's the million dollar question with clients is, well, how much water? That's always an observational science because you want to know how much water have you had recently? If it's been really dry, you're going to try to put more down. That screwdriver test helps you tell how dry your soil is. If it's more of a quick maintenance water or you're trying to get it a big overhaul because you've had too much dryness. Yes, if you're doing a DIY watering and you can put your hose out, they say the general watering might be somewhere, 5 to 10 gallons per trunk inch of diameter that your tree is.

That sounds like a lot of water, but in one single watering that might try to carry that tree for a month in the off-season. That's the water it's looking for, but you're also always relying on Mother Nature to help carry the bill a little bit too. Otherwise, it's a ton of water to try to put out manually. We always refer to it as a supplemental water to give it some relief from drought, but it's tough to give trees every ounce they need just by humans. You're always banking on some weather systems to help.

Doug: Does the amount of rain that comes down, does that determine how often you go out to a property?

Michael: Yes, and when we have systems that move through, we'll generally shift, do some other types of services that we can do. Then once things dry up, we're calling people to come out and do the watering. For the Colorado dryness that we get, that moisture might only be a flash in the pan that helps bridge the gap for a week. We could be on the heels of a storm or right after a storm and still go out and water and provide benefit because stuff dries out that fast. This year was weird. We had record rainfall and totals of precip spring and summer. It was the wettest year I've ever experienced my whole life here. Then it's dried out so bad that we're back to below average for our conditions.

It was just like a two-sided story of tons of moisture in the spring and the summer and then nothing now recently.

Doug: With that tons of moisture, what problems does that bring up, or are there any problems with that in your climate?

Michael: Yes, for us we celebrated the moisture for the most part because our trees had record growth rates on a lot of the branches and twigs and it just showed how successful our trees would be if we had different weather. I got that taste of what Seattle trees get to experience and how successful and healthy they look. They all perked up from the one year we had here with all the moisture.

It brought a few other disease factors a little bit higher that we don't generally deal with as bad. We are so dry that the disease pressure is that low and this year it was like, okay, we saw an uptick in a few different tree diseases. It made our fire blight season a little bit heavier with crab apples and stuff like that. It was like worth the sacrifice to actually get the moisture that trees should have that we pretty much never have in the front range of Colorado.

Doug: As a tree guy, tell me a little bit about the feelings of that because I know as a gardener, when you've got all that rain, it's such a great feeling. When you don't get it, it's such a terrible feeling. From your point of view as a professional, touch on that a little bit.

Michael: Yes, it was like one of those great years where lawns were just green, taking care of themselves. The trees were so happy and put on so much growth. That was just a total blessing this year. It was almost a challenging year just for going out and doing work because of how often we had rain and we're really not used to it. I'm sure there's places in the Pacific Northwest that their crews would laugh at our struggles with us working in the rain because it's so unusual for us.

The trees were doing so great with it and it definitely makes you feel like it's just a good growth year. Trees are healthy. Now that the faucets shut off, it's back to that anxiety of, "Okay. We're back into like a drought pattern. I got to get home and water my trees today." You start to think about it a little bit more. It was autopilot spring and summer, which is awesome.

Doug: For a homeowner, when you're coming there to water their trees, are they paying by the gallon, or is it a set fee, or does it depend on the client?

Michael: The cost is always just based on the estimation of time it's going to require or their tree count at a certain cost per tree type of situation. They know the cost, and it's just built into like their plant healthcare program that they've got winter watering at X cost per application. When we get these dry patterns, we'll have clients calling us saying like, "Please add another watering, or, please set up the watering that I thought I was going to do myself and turns out I'm not into going outside over the winter and watering the trees on my own like I thought. Go ahead and send out your technicians, please."

Doug: That's good they're doing that though, because let's talk about the importance of water for the tree. We've touched on it. Like you were saying, when you get all that rain, you saw what the trees are supposed to do in the Denver area, but it's important they get their water. You do not want to withhold that water.

Michael: Yes. All of the root growth that they put on, you have tons of fine little root hairs that probably all shot out and explored all the moisture in the soil earlier in the season. Those are the most susceptible ones to dry up and die back. Similar to how you could see a canopy die back from different health issues, your roots could do the same thing underground if it's too dry. That moisture helps with just preserving your year-over-year growth and having the tree able to have its resources to access with all of the roots so that your canopy does well. If you put on a bunch of root growth and then all those roots die back, that withholds your canopy from being as successful too.

Everything was firing on all cylinders in the spring and summer this year from the moisture that all of the new twig growth on the ends of branches was record lengths that I've never seen. It was refreshing to see what extra water does for us in Colorado. It highlighted the importance of it because seeing what was possible with moisture versus what we generally see just showed that watering, including in the wintertime, is the big difference maker for us for tree health.

Doug: Where I'm at, the soil is clay and/or shale. Remind me again what soil you're dealing with out there.

Michael: We are pretty predominantly clay with high soil pH. That's if you ever had to just put your money down on what somebody's yard is going to be dealing with, it's that. Holds moisture well, but it's also hard to get moisture in. It's hard to dig holes. The high pH ties up other nutrients that help with some trees. We get a lot of chlorotic trees for iron deficiencies because of the high pH. That's generally what we're dealing with here. In newer developments, the soils that the houses are built on and the yards are built on were just prairie grass.

There's not a lot of organic matter and nutrient cycling that happened for those hundreds of years in the prairie that the person now just planted their tree in. The nutrients are pretty hard to come by compared to where out in the Midwest, you've got old forest soils and you've got soils that have organic matter and they're darker in color. We don't really have that here in most places.

Doug: What's interesting is a lot of the housing development here is on old farmland, which they usually strip off whatever the good stuff they can get. Then we're stuck with the same thing you guys are stuck with. Now as far as your pH is concerned, when you're planting a tree, are you choosing a tree that can handle that pH, or are you trying to remediate the pH or both?

Michael: It's tough to get a pH change with soils. Generally cost-prohibitive to try to change your soil pH. We just know which species are going to have a tough time with it. If you're planting your standard autumn blaze maple or you're trying like a red oak tree, those are some of the big ones that we know like, "Okay, you can plant this, but if your soil pH ends up being a problem for your iron, you may have to be doing some iron supplements with these species or iron injections when they're older to try to correct that." People love planting their maples and oaks anyways, and then just deal with the consequences later if they end up having a chlorotic tree and they do treatments.

Doug: Yes. People are always asking me like, I want my hydrangea to be a different color. How do I change the pH? I say, good luck. [laughs] Yes, exactly.

Michael: Yes. It's one of those things you just have to know about.

Doug: Yes. Really hard to do. You did say something though, you continue to fertilize during this period too. Is that right?

Michael: Yes. We try to do our fertilizations just on a one-year cycle with people's tree care. Our Arbor Green Pro lasts about a year plus in the soil. You're just maintaining that. If somebody hasn't fertilized their trees and you're getting them set up with tree health care programs, it's generally like, yes, let's get some food in the ground as soon as we can, start to get those trees accessing nutrients and getting ready for better growth. Even if it means you're injecting it at a weird time of year to most people, because people are on that lawn for a schedule of like, "I only fertilize my lawn, spring and fall. For the tree care, because it's slow release nutrients, just like a good soil would have in the forest, you just want to put it in there and let it start working and getting trees fed."

Doug: Michael, this is good stuff. Before I let you go, let's talk trees a little bit. What do you like to plant there when you find the right spot in Denver?

Michael: Yes, I'd say trying to diversify is our big goal, because just like how everybody overdid elm trees, felt the consequences from Dutch elm disease, ash is your next.

Doug: Yes. Ash trees out here.

Michael: Yes. We're dealing with emerald ash borer in Colorado and everybody that's over-planted ash are feeling the pain. Maples are honestly the next one that was overplanted because autumn blaze maples are so attractive to people with the red fall color, but they became a monoculture pretty quickly. I'm generally trying to diversify, get somebody a new species on their property that they've never had before. Pick trees that are a little bit tougher for the drought and the heat.

I'm looking at a lot of Kentucky coffee trees, catalpas, hackberries, trying to get a little bit more off the beaten path so that people don't have the monoculture. Then the trees are a little bit better with hardiness. We don't have a lot of oak planting, so that's picking up in popularity a little bit. The big thing is just avoid the monoculture again, because that's been just a decade after decade disaster with trees that people have just picked the same attractive ones that check all the boxes for flowers or fall color and repeat plant them everywhere versus new species for every single spot you're planting if you can.

Doug: It's funny about trees, for me, I have a special place in my heart for catalpa because I had a huge one behind my house growing up. It's a tree that a lot of people don't know about. It's a real beauty. Those seed pods are awesome.

Michael: Yes, I agree. They're white flowers that are summertime after a lot of other things are out of bloom, are really refreshing. They look tropical almost. The leaves are huge, so you get great shade. The pods, depending on your-- yes, some people love them. Some people hate them. I always warn people that they have pods before they plant it in case they're like a lawn person that can't stand to see any debris in their yard. They rake up real easily, so they're not too bad. They grow fast.

Doug: I know. I raked them up from age 5 to age 18. [laughs]

Michael: Yes. They're not too bad of a mess. Yes, I definitely like catalpas. They have really unique growth habits, generally a large trunk too. When they become stately old trees, they just look really impressive.

Doug: That's what we had. Again, the downside is the pods on the ground, but the pods when they're on the tree, explain how big those are.

Michael: Yes, they're like over a foot long. They look like a stretched-out cigar. They're brown to tan in color. Yes, they're great for kids to throw at each other, right?

Doug: Oh, yes.

Michael: Little sword fights.

Doug: Oh, yes.

[laughter]

Doug: All right, Michael, I appreciate you talking to me again. That's great stuff. Great information, and I'm sure we'll talk again. Thank you so much.

Michael: That sounds great. Thanks for having me again.

[music]

Doug: Tune in every Thursday to the Talking Trees podcast from the Davey Tree Expert Company. I am your host, Doug Oster, and do me a big favor, please subscribe to the podcast so you'll never miss a show. If you have an idea for a show or maybe a comment, send us an email at podcasts@davey.com. That's P-O-D-C-A-S-T-S@D-A-V-E-Y.com. As always, we like to remind you on the Talking Trees Podcast, trees are the answer.

[music]

[00:22:13] [END OF AUDIO]