Best Summer Tree Watering Tips to Follow

Dan Cohen, from Hartney Greymont, a Davey company, in Needham, shares some expert watering tips to keep your trees hydrated all summer.

In this episode we cover:  

• What's the first thing you think of when watering trees? (00:51)
• Watering newly planted trees (1:28) (5:32)
• How rainfall has been this season (2:51)
• How arborists handle dry conditions (4:00)
• Using tree gator bags (7:15)
• Watering ornamental trees (8:50)
• Properties using drip irrigation (11:07)
• The best time of day to water (12:12)
• The right way to mulch (13:50)
  • Rubber Mulch (18:50)
  • Gravel (20:00)
• What Dan enjoys about being a Davey Tree arborists (21:30)

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

To learn more about keeping your tree healthy during the summer, watch this ABC10 segment.

To learn more about watering your trees head to our blog to read all about watering.

Connect with Davey Tree on social media:
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Facebook: @DaveyTree
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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

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 this week by Dan Cohen. He's an assistant district manager in the Boston area for Hartney Greymont. It's a Davey company. Welcome to the show, Dan.

Dan Cohen: Hi, Doug. Thanks for having me.

Doug: I just did a video. It says, "I hate watering." Even though I hate it, I know I have to do it. What's the first thing you think of when thinking about watering trees?

Dan: Just like you said, I don't like to have to give anything more water and use our valuable resources when it's unnecessary. Certainly, watering trees, especially new trees is key bit of establishment, but also is really important for life. I think typically what I'm guiding folks is lower volumes for a longer period of times, good saturation as opposed to shallow, more superficial quick waterings, or even watering foliage, which is again, something we can get into, is really bad for trees as opposed to just watering the root zones.

Doug: Let's talk about newly planted trees because lots have been planted and are still being planted right now. I'm sure watered right when they're put in, but then after that, how often should we have water on them?

Dan: Of course, certainly, that's something we advise our crews to water during the installation process or shortly thereafter. So much of the amount and volume depends on geographic location, time of year, weather, location. Typically, if it's done in the spring and we're having a normal precipitation-filled spring, that's great. Maybe it's once or twice a week, depending on the rainfall, especially during the summer, when it becomes less or more sporadic and rainfall and either torrential downpours and then nothing. I'm watering two, three times per week, depending on location.

Again, doing that heavy trickle water for a longer period of time, really let that water saturate into the root zone, give the soil a few days to start to dry out and then re-saturate the area. That's the way to go. A lot of it just depends on soil moisture, weather, how hot it is, some other environmental conditions if it's around a street or sidewalk, which may dry things out or warm up quicker.

Doug: How has your rainfall been so far this season?

Dan: Better than last year. That's a great start, having very little last year. I just checked the local Massachusetts drought monitor, and we are not in the abnormally dry where we are just outside Boston. Cape and the islands, parts of Western Mass or Berkshire are in the abnormally dry, which is I think the level just before drought. I also noticed that it said we typically was 2 inches of rainfall for month of June, and I think we're at about an inch. Lower than the average, but better than last year. Again, it's not as dry as last year was, but still fairly dry out there.

Doug: Anybody who works with trees, works with plants, and works in the garden knows that it's much worse to have less water than more. It drives me crazy because again, like a lot of people, I hate watering, but you can't ignore it. It's got to be done. From your position, from your job, when you have dry conditions, how does it make you feel? [chuckles]

Dan: It makes me a little, I don't want to say nervous, but maybe engaged and on guard because the first thing, nowadays, a lot of folks want to talk about is, what can I plant that's tolerant to drought conditions or lower maintenance? Two things I always talk about is, one, we're not planting palm trees up here yet even though we have some warmer winters, mild winter like last year, we still have that negative 20-degree temperature for multiple days. We still look cold extremes on that front.

As far as lower maintenance, less water input plants, anything is going to need that initial water. I always try to tell folks it's going to need any new tree, even if it's a succulent, it's going to need some extra water initially at first season, first couple of seasons. The hope is going forward, you're just supplementing during the driest times, so the summer, so just trying to be smart about the watering.

Again, can they put the watering bag that helps? Can they put a hose on a heavy trickle and just leave it for a couple of hours moving around in places and doing that once, twice a week, depending on the environment? Just trying to be mindful of how the watering can be more, not just efficient, but more effective, and not just, "Oh, I sprayed the surface real quick, everything wet, and walked away." You can do that every day and not do actual solid watering as opposed to less frequently, but larger amounts, larger volumes of water.

Doug: You said something really interesting there about the newly planted trees is how long you do have to keep water on them. Talk again about that. This isn't just when it's planted. This isn't just for a month, but a new tree, especially spring-planted tree can need water all summer long and certainly until the ground freezes.

Dan: Of course. A lot of people have a misconception. If there's no leaves on a tree, you don't need to water it yet for deciduous trees, but actually, the roots are still active when the soil is above 40 degrees. Even if you put a new tree in April, not very warm outside, but the ground is warm enough, the roots will be actively trying to take water and grow and respiring. You just going to make sure that there's enough water in the soil in the spring and then ongoing once that trees in.

One of the most important factors with a new tree, new shrub, most of them have been transplanted from nursery, their roots have been cut to make it into a transportable size, so making sure that not just the whole area underneath the tree canopy, but actually just what is the new root zone is more specifically watered, but then also water in the area beyond that, so now these roots can start to grow beyond that planting hole and expand.

The other part about the root growth is you really want to encourage roots to go further down and spread out so they aren't relying on one area where the water is constantly and they just become enclosed to that one spot where the water is. You want to encourage them to go seek out the water, to go deeper and just become more inclusive to the area where they're going to have a better response. We do have a drought or a time of less water.

Doug: The tree bag, is it called a Treegator? Is that right?

Dan: Yes, yes, Treegator.

Doug: How do you feel about those?

Dan: They're okay. They're better than nothing. Typically, that's just on a brand-new tree. Some issues is people leave them on for too long. It keeps moisture in the trunk and cause issues. A lot of the municipalities around here have actually gone to when they install guide stakes to support a new tree. They actually do that for a few purposes more to show it's a new tree, gives a lot of protection, and they actually put the gator bags, two of them around two separate guide stakes. That gets the water just to the edge of the root ball there. It doesn't cause any trunk issues. It's just another point to stand out to new tree.

Folks, I think, more often should use them if they're in urban conditions, like a sidewalk, a street-side planting where you don't have access to a hose. You can't leave a hose across the sidewalk during the day. It becomes a tripping hazard. They have their use, but that should really just be the initial planting and not long-term.

Other ways to go about it might be taking a 5-gallon bucket and drawing holes in it, small holes where the water can slowly drip out, so much we just make sure it's the right volume and the right amount of time, and those water bags you could fill up in typically between 2 and 5 gallons they drain pretty quick. In an urban environment, you might need to be filling those once or twice in the spring, but it could be between two and four times a week in the summertime, given the different circumstances.

Doug: Then how about trees that have been there for a while? Do I water them or do I just wait? Certainly, I've got some big giant oaks that I wouldn't water. I couldn't even wrap my arms around them. Smaller trees that have been here maybe three, five, seven years, when should I consider doing the same thing to just letting the water drip down in there?

Dan: Of course, it's hard to quantify the volume of water that a mature tree needs. It's typically thousands, thousands of gallons, so pretty hard to supplement that. Certainly, in ornamental trees to look at a tree and say, "I'm not going to wait till I get stressed out, but we're having a dry season like this, or last year.

Like I said, maybe if you have a garden, putting it on the hose on a heavy trickle, so it's flowing out, put it at one edge of the canopy, underneath the canopy, let it saturate in for half an hour, an hour, move it 5, 10 feet away, doing that for probably a couple of hours per ornamental tree, and then doing that maybe once or twice a week during the driest time, so really when it's hot and we get no rain. Keeping an eye on the weather is important. Thunderstorms are great, they can cool things down, but usually it's such high volume of water so quickly it either runs off. If the ground is really dry, it becomes hydrophobic and won't even saturate in. Actually, if you've pre-watered your area, the area below your trees, when it rains it's actually more likely to capture that water and infiltrate the soil as opposed to just running off. Thunderstorms are just unreliable as a source of water, short of gathering it and using a rain barrel or something.

That is one way if you have no irrigation. If you have drip irrigation, maybe supplementing ornamental trees that have been established or have been for a couple years, giving them some amount of additional watering during really, really dry times. Again, those summer months is really just going to help the tree out. You can usually notice some of these issues of trees when the leaves start drooping, when it's really hot, especially some of that really hot baking afternoon sun. Just getting some water into the root zone first thing in the morning is the ideal situation.

Doug: Do you have properties that you guys maintain where they use drip for the trees?

Dan: Yes, the majority of the properties we maintain if they have drip, it was likely installed when the trees initially got installed. Those couple of rings of drip were below the canopy at the edge of the root ball likely have outgrown that. Sometimes real specific properties, real key feature trees will come and they'll add additional rings to spread out as a tree gets larger.

For the most part, there's some amount of irrigation on a property between drip, overhead spray sprinklers that typically would water the lawn. Most of the folks that have those systems are running them at some point throughout the season, whether to keep the lawn green. That's probably not the best type of watering because it's more superficial stays towards the surface, the turf absorbs a lot of water, but still better than no water. Having that the drip zone and other soaker hoses, irrigating established trees is really beneficial during that hot, dry part of the summer.

Doug: Is there a time of the day when it's best to water?

Dan: Yes, so certainly the morning. If you had all things being even, first thing in the morning, as the sun's coming up, even before the sun's come up, get the water in the ground. A couple of reasons, it's there. As the day gets hotter, the moisture is in the soil. If you're watering, you can't avoid watering some of the foliage, especially if you have a sprinkler that stays on there overnight, it's going to cause issues. If it's put on in the middle of day, it's going to magnify the water. It could burn, basically, scorch the leaves.

First thing in the morning is really the ideal time to get it in there. It gives it time for the plants to dry off and just really to absorb the water as the day starts heating up.

Doug: I hear from a lot of gardeners who want to water at the end of the day thinking, "There won't be as much evaporation," but Dan, isn't that the problem that there isn't that evaporation?

Dan: Exactly. When you have the moisture sitting on, especially if you're using a hose and you're watering overhead, and we call it overhead because it's coming from above there, it's the water staying, there's no evaporation, so it's just sitting in place, that's when you tend to have more issues with fungal infections, just water sitting in place. It could be issues if it's close to homes. If you say it can only water once, and that's the only time I have, yes, sure, it's better than no water that day.

Ideally, if there's a perfect time, it would be first in the morning, so the plants have it when they need it. The day was 95 degrees, new water in the evening, the plants are already going to be stressed from the lack of water in the soil from earlier that day.

Doug: I guess we should talk about mulch too. We talk a lot about mulch here on this podcast, specifically volcano mulch. Let's talk a little bit about the right way to mulch and how that helps us with our watering.

Dan: Of course, yes, so mulch is really a great tool to use in the landscape when done correctly. As you mentioned, Doug, the volcano mulch is a typical, we'll just put mulch around the tree, and you'll mount it up nicely, so it looks like a nice volcano to the tree trunk, which is really not ideal. One, when you have the mulch contact in the trunk, it keeps moisture there.

The tree trunk, tree branches are much like tree roots, except tree roots were meant to be underground, and tree trunk and branches were not. When they constantly have moisture, you can have fungal issues, you can have disease issues, you have insects that come, you have decay. Avoiding the mulch contact in the trunk is probably the first thing, then probably having the proper level of mulch. Only having maybe 2 to 3 inches at most around the base.

Too much mulch can just basically actually inhibit the root growth and encourage your roots to stay on the surface. We talked about earlier, you want those roots actually to go down further and deeper into the soil. Also, having the right type of mulch. It's great to buy bagged mulches. Unfortunately, a lot of bagged and dyed mulches are just, ground up pallets that have been dyed. They look great, but they're not adding a lot of value to it.

When you have a good age wood chip bark mulch that has been double ground, it has leaves, twigs in there, it's actually adding something to the soil. It'll be a soil amendment over time. It may not hold its color depending on what plant parts it's made from, but it's going to actually going to add to the soil, and actually going to invigorate and amend the soil over time as it breaks down and decays as opposed to these what are old pallets, it was likely larger, more dense wood material that really doesn't have much nutritional value to it.

Doug: Tell me if I'm riding along in the truck with you and you look over to your left and a group of landscapers that are volcano mulching up a big oak tree. What am I going to hear?

Dan: It's going to just be some snarky comment about, "Look at that Mount Vesuvius over there," whatever it might be, whatever volcano I can think of offhand. Again, a lot of it's not for lack of trying. They're trying to do its best, the best intentions, just don't have probably the knowledge behind why that's bad to do that.

They're trying to come in quick. They're on a limited budget and timeframe and they're trying to make things look nice. Then more often than not, just don't understand the science behind and the more issues they're actually going to because if they put too much mulch in one area as opposed to not enough.

Doug: You'll get arguments. You'll get arguments. I'm certainly not going to stop and argue with anybody, but with you, you've got science behind you. We try and tell people the right way to do this, but it's become so prevalent. People see it and they want to repeat what they see, I guess. I don't know. I don't understand.

Dan: No, I think--

Doug: I visit these properties just to talk about gardening with them. The first thing I say is like, "Come on out here. Let me show you what happens. How much mulch is on these trees. This is not good." You've got to tell them this isn't the way to do it, but these landscape companies will resist.

Dan: Much of what we do is educate our clients and tell them. Again, like you said, bring them out there, excavate the mulch and show them. Unfortunately, depending who's done the planting, especially if we have not done the planting and not that there aren't good landscapers and arborists out there, but a lot of times the tree itself is planted too deep, nevermind the volcano of mulch on top of it.

Trying to pull away that excess mulch, pull away the excess soil, and show them the root flare, walk me over to a tree at the edge of the wood line that's, naturalized planted itself, planted itself at the correct depth, you can show them that root flare where the trunk winds to the roots, show them that that's the ideal location for above ground exposure, and then walk back to the volcano tree. It looks like it was a telephone pole, just go straight into the ground.

Then again, educating, explaining why this is bad, what could happen, the negative benefits. Usually, once you've done that, it's understood. I know I've had clients who go around and say, "Oh, look at these mulch volcanoes everywhere," mulch volcanoes because we've educated them to a point where they see that and they know it's not a good thing, and they now will joke with other people about their mulch volcanoes.

Doug: Let me talk about two other mulches and get your opinion. Let's start with rubber mulch. I was walking through a big store the other day and I saw bags of rubber mulch, which I'm sure to homeowners might seem like a great idea. Gosh, I only have to put it down once. What do you think about that?

Dan: I have never seen it other than as a substrate for any playgrounds, which is probably a great area. I think it's probably a terrible idea for the garden because just because you put it down once, as we all know, with gardeners, weeds are going to come up regardless of what you put down short of a new layer of plastic every year. That just seems like it's probably not a great idea. I don't know how it's going to affect the soil, but I can't imagine it'd be great as far as what comes off of it, the leeches, if it breaks down in the sun.

The only other thing I can consider is if you've had an urban environment where sometimes there's certain types of pavement, a permeable pave or a soft pavement that's basically small rubber pieces adhered together, that's a different situation, but as far as bag rubber mulch, I would probably advise against. I don't think it's adding anything and probably going to complicate mid-gardening. Much more of an inconvenience in that area.

Doug: The next one is gravel.

Dan: Gravel is certainly better than the rubber mulch. That is probably more an aesthetic concern. It's not adding any nutritional value to the soil. It's just straight bedrock, whatever type of stone or material it is. It actually and sometimes can keep an area cooler. It's typically a lighter colored, so that's going to reflect more heat as opposed to absorb it if it's in a sunny area. It might make weeding a little bit easier. Again it's not going to add anything to the soil.

In this perfect world we live in the reason why we want reasons we mulch is not just aesthetics but it helps to amend the soil. We love to remove leaves from our urban environment because it looks nice. It's neater when the leaves are gone. That is a natural recycling and mulching method for trees. Without the leaves which we then haul away, you want to add some sort of fertilizer nutrients back to the soil. Mulch is one way you can do that.

Again, the gravel I'm not fully against. It probably has its application when it's a little formal garden of some sort. It's just going to know that you aren't adding any nutritional value there so you might want to find other methods to do that. Then, again, if you are doing any additional gardening, it's great, and like anything, but over time small debris is going to build up. If you see how forests are grown, it will accumulate, weeds will grow, and then still other gardening concerns that come in. It's never fun to dig a shovel right into the gravel. Long term, I can see the issue is not very highly maintained.

Doug: Dan, before I let you go, something you mentioned earlier is the teaching. Talk about what you get out of educating your clients.

Dan: Yes, so much of our job, my job, my associates' job is arborist, and almost all of us certify arborist is education. Obviously, we have services we can provide. We go from plant health care, insect disease controls to tree removal. Although tree removal is not our specialty and we'd rather preserve a tree if possible. Really just comes down to when you walk onto a site, take a look around assessing the property, and then talking to the homeowner about what's going on and educating them.

"Here's what I notice, here's what I see. Is this tree important to you?" Talk about what you notice. Whether it's the insect issue or an insect that's there that's not an issue and again educate them. "Oh, that's actually a beneficial pest or beneficial insect that's going to eat pests," or, "Hey, you have a mulch volcano here. You have all these invasive trees that may not be an issue now but are going to be an issue."

To me, actually, talking with folks and explaining to them using the knowledge that I've gained over my years in this career, my 19 on, off years in this career, my education, my background, urban forestry, it's really great when I get to share information. I don't need to hoard information myself. I learn it, but I like to share it and guide others and have them make decisions based on my recommendations, what I'm noticing out there on each property.

Each property is different. Some can be the same, but each property has its own plants, its own little microclimate, and then the homeowners themselves. Some people love their trees, other people it's just an inconvenience. I get a rake, I get a water. Why do I even have this? Just trying to manage people and then manage their trees and educate them so they can make sound decisions.

Doug: I'm going to leave it right there, Dan. That's good stuff. Thanks for schooling us on lots of great stuff. I appreciate your time and I'm sure we'll talk again.

Dan: Doug, thank you. I appreciate talking to you. Take care.

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 favor subscribe to the podcast so you'll never miss a show. Next week, it's pests versus beneficial insects, an in-depth look at our trees and their connections with those insects. Got an idea for a show or maybe a comment, send me an email to podcasts@davey.com. That's P-O-D-C-A-S-T-S@D-A-V-E-Y.com, and as always we like to remind you on the Talking Trees Podcast trees are the answer.

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