How You Can Successfully Grow Trees in Containers

Lou Meyer, business development manager for Davey's Mid-Atlantic region, explains the practice of growing trees in containers and how you can ensure these trees thrive in your small landscape. 

In this episode we cover:  

• Why do we use containers to grow some trees? (1:26)
• What trees can you grow in containers? (2:35) (7:04) (9:04)
• What are some of the planters made out of? (3:38)
• What do you fill the planters with? (4:28)
• The emotional impact of trees (10:31)
• Watering trees in a container (11:37)
• Fertilizing trees in a container (12:44) (13:09)
• Mulching trees in a container (14:57)

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

To learn more about the best trees to plan in containers, read our blog, Can You Grow Evergreens In A Container?

To learn more about soil care for potted trees and plants, read our blog, How to Refresh Potted Plants by Changing Soil. 

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

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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 by Lou Meyer. He's part of the Davey Business Development Team in the Mid-Atlantic region, based in Baltimore. Lou, you say we can grow trees in containers?

Lou Meyer: We can grow trees in containers, but we can grow all sorts of things in containers. What we want to talk about today is how to use containers on your property, why, and some design principles that might help guide you to success.

Doug: All right, well, let me tell you a story. I worked with a news anchor and she brought in a plant marker one day and said, "Hey, Doug, I'm putting this magnolia in a container on my patio. What do you think?" I looked at the plant tag and I said, "Brenda, this thing's going to get 30 feet tall." She says, "Oh, no, no. I'll just trim it off at the top and keep it right where I want it."

[laughter]

Doug: That's not going to work.

Lou: I would love to see how Brenda's magnolia looks today.

[laughter]

Doug: I don't think it looks very good. [laughs]

Lou: No. No.

Doug: I don't think it survived.

Lou: No, probably not. Growing trees in containers can be difficult, but there are times when you have to. Why do we use containers? Let's talk about that first. One is for limited space, right? If you're in a condo with a small patio out back and you don't have space for a large tree, if you only have a deck, if you're an apartment with just a deck out, and you think, "I can't grow anything." No, you can. You just have to get creative and use containers.

We also use them as garden accents. A centerpiece in the middle of a planting could be really catching. We can use it as bookends on a porch to have that introduce different materials. I like using them to accompany verticals. If you have columns, to have tall planters at the base of them to bring that art down into the garden, it could be really nice. Then for color splashes. If you have a white or gray house, to have some beautiful ceramic planters with bright colors popping can contrast greatly. All sorts of ways to use them.

Doug: Are we picking a tree that stays reasonably small, I assume?

Lou: Yes. I've seen containers with Japanese maples in them. Now you have to use a big container. These aren't the 2 gallon, [chuckles] little ones that you find somewhere. These are containers that are built for trees. We recently planted three trees on the roof of the National Aquarium in Baltimore, actually. Part of their greening up of the property. We had to use a crane to lift three giant planters. These are 6 feet in diameter. I can't remember the total volume of these, but 6 feet in diameter and 5 feet deep.

We planted two evergreens and actually a magnolia, I think it was. I can look at my notes, but we planted those. There's no soil up there. There's no way to plant them in a bed. We had to do that, but they're gigantic planters.

Doug: What are the planters made out of? Are they like a stone? Something that had to be heavy, right? If you're going to put a big tree in there.

Lou: Yes, they were-

Doug: Are they ceramic?

Lou: -heavy. These three in particular were concrete. It was a lightweight stone. It had to be heavy because it's exposed to the wind up on the roof. We needed a really strong anchor. We even anchored it down from there. We needed a strong anchor, but you also need it light enough that you can lift it up onto a roof. It would take probably 10 guys to move it around. Luckily, we had a crane that positioned it for us. Yes, that was stone. You can get them in stone. You can get them in ceramic. Metal planters can be really pretty when used the right way. Plastic planters can be used. They're lightweight. For a budget choice, it's definitely an option.

Doug: Let's go back to that rooftop. What are you filling up that size container with? After you take a crane to put that up there, does the crane also take a pallet of something up there to put in there?

Lou: You betcha, yes. For this project in particular, we had soil that was designed by a soil company back in the Midwest. The landscape architect put together all the specs on what we had to use. Yes, it was a custom soil blend. It's not lightweight. A lot of times in containers, you want to use what's called a potting mix if you're planting a container in your garden or in your house.

It's important to note, potting mix and potting soil are two different things. Often confused, but two different things. Why they both use the word potting, I don't know. Potting mix, what you want to use in your garden containers is mainly peat moss with some nutrients. There's no soil in there. More importantly, it's sterile soil. There's no seeds. You don't have weeds in there. You don't have to worry about weeding out your containers. Now, over time, if you have a container that's out front for 10 years, even less than that, a couple of years, you'll get weed seeds popping up from birds and squirrels and other things, and wind. Right off the jump, you don't have that.

Potting soil, on the other hand, is a mix of loam, peat, some soil, usually some sand and nutrients. It's heavier, it's non-sterile. You use that more for garden soil. Garden soil is a good mix with potting soil. All this as opposed to just straight soil. If you get soil or you backfill, that's just dirt, for lack of better words. In these planters, we used a custom soil blend. We put down gravel at the base for drainage.

Doug: Right, drainage.

Lou: Then we put down the soil, planted the trees, put a layer of mulch on top, which is how you want to plant a container tree. The National Aquarium, they have a full-time horticulturist on staff. They're hand watering it daily. They have other plants up there that they use in their displays. If you are doing this at your house, you'd want to either get a self-watering system, so an irrigation line that plugs into a self-watering planter, or at least put drip irrigation in there if you can't get out there daily to water. One of the downsides of containers is they dry out really quickly because they're exposed.

Doug: Let's talk about some species, some trees that you might think about. Again, right tree, right place, but we can't grow a 50-foot tall tree in a container. What are some of the things that you would think about for the regular homeowner that they could plant in the container?

Lou: Yes. Japanese maple is a good example. Those stay fairly small. I think a Kousa dogwood could do okay in a container. One of my favorites is a serviceberry, Amelanchier. You get the autumn-- autumn splendor, I think it is. It's one of the prettiest trees in the world. A great four-season tree. It's got spring flowers. It's got a heavy spring flower set. Fruit in the summer that the birds love. It's called a Juneberry, so it attracts birds if you're a birder. Spectacular fall color. Then, when that falls off, the bark is this crimson color that peels, like a river birch. You got this exfoliating bark. Man, it's a winner. I would do that.

Paperbark maples also could probably do okay in there. Paperbark maples have, similar to the serviceberry we just talked about, has the exfoliating bark with the color that's just gorgeous. They stay fairly small.

Doug: How about some cool, small evergreens? Could we do that?

Lou: Oh yes, absolutely. You see that used a lot on commercial properties. A lot of times, commercial properties will have emerald green arborvitae and planters. Those are the arborvitae that are about 4 feet-- they get to 2 to 4 feet wide and about 14 feet tall. They're just tall, skinny trees. If you live in the Midwest, there's one on every corner of every house.

[laughter]

Lou: Back in Ohio, I saw them everywhere. We use them a lot here too, but those can do well in containers. There's quite a few dwarf evergreens that can live in containers just fine.

Doug: All right, I have one I want to throw in the mix.

Lou: Sure.

Doug: I don't know if you know it, but it's a rose of Sharon called Sugar Tip.

Lou: I don't know that one.

Doug: It is sterile, so it doesn't make babies. It only gets up to maybe about 15 feet tall. It has variegated foliage and beautiful double pink flowers.

Lou: Ooh.

Doug: I was finally able to add something to the conversation with you, Lou. That's a first.

Lou: Oh, I love it. The Sugar Tip, I'm writing it down.

Doug: Yes, that's a cool-- and there's actually one also with a golden variegation instead of white. I think it's called Golden Sugar Tip, something like that.

Lou: Oh, cool.

Doug: People hate rose of Sharon, you know that.

Lou: Right.

Doug: Because it makes so many babies. I actually love rose of Sharon. I brought rose of Sharon from my old garden. People think I'm nuts, but, Lou, trees have a special meaning. You know how that is. For me, my kids growing up were playing basketball next to that rose of Sharon and that rose of Sharon took a beating from 10 and 12-year-olds playing crazy basketball games. I just always remember my kids when they were little, my oldest is going to be 40, so this was a long time ago. I just remember them playing under that rose of Sharon and so I brought a couple from my old garden. Now I've added the Sugar Tip to my garden and then when we started talking about containers, I was thinking, "Wow, that Sugar Tip would be perfect."

Lou: Yes. Yes. No, that's a great story. To follow up on it, it's amazing how many stories I hear from clients about the trees themselves and it's not just an accessory that happens to belong to the house, but "This is the tree that my kids had their swing in" or I, myself, I grew up in Sycamore Township, which is a suburb of Cincinnati and I love sycamores. I think it's because I heard it so much growing up. You grow up on Elm Street and you love elms. No, trees have an emotional impact on us that we don't often realize. They're living creatures. They're not human, but they're living creatures. We interact together and they benefit us in so many ways.

Doug: It's sad when you lose a special one.

Lou: Argh, can be devastating.

Doug: Being a tree lover, that's part of being a gardener. Plants die and that's just the way it goes.

Lou: Oh yes.

Doug: Whether it's some crazy disease coming through, crazy invasive insect or just old age, whatever it might be. Now, I wanted to ask you, we use a formula for our containers that are smaller with flowers. We have a thriller in the middle, which would be our tree, then a filler next to it and then a spiller out the sides. Could we do the same thing with our tree container?

Lou: You can, yes, absolutely. You put the tree in the center, maybe some decorative grasses around the base of it. When you're doing the thrill, the spill and the fill, not only are you looking for different heights and different growth patterns, but also different textures is really good and different colors. You want to have contrast. Yes, if you have a broad-leaf deciduous tree up high, some grasses at the base, now it's going to be shady because you have a tree growing over it, but you can get away with say Japanese mondo grass. That's a fine one that can take shade. That'd be a great filler. Then spills coming over the side, all sorts of opportunities there.

Doug: Yes, I'd probably use some shade, annual fuchsia or something like that. You'd get the color and you're softening up the edges.

Lou: Yes.

Doug: We've talked about watering. What about fertilization?

Lou: Yes, so you want to make sure to fertilize. If you have all these trees in a container that is not replenishing the nutrients, you're going to need to do that yourself. Yes, make sure that you're fertilizing along the way so that the trees, the shrubs, the flowers have food to create their carbohydrates.

Doug: Normally, for a tree that's in the soil, you guys come out and you have the liquid fertilizer that you put in with a probe and it's slow release. What stuff would I use for the container? Would I use the same thing or how would I do it?

Lou: What I would use for a container, especially for a homeowner, are those tree spikes. Now we don't recommend those for-- Sorry, to back up, tree spikes are not spikes that you [laughs] push into the tree. They're spikes that you shove into the ground and they slowly disintegrate and work their way into the soil. We never recommend those for trees out in your landscape. The reason why is for even a 10-inch maple, you're going to need a ton of those spikes. The application rate is wild on a tree. It's much more efficient and cost-effective to have an arborist perform a deep root fertilization.

The other thing is those spikes only get 4 to 6 inches down in the ground. They're in the root system of the turf still. What we need to do is get under that root system of the turf with our 8- to 10-inch probes down to the root systems of the trees to deliver those nutrients right where it's required. While we're fertilizing trees with our deep root probes, we're also slightly fracturing the soil which aerates it along the way, which is necessary in a clay and soil mix that you have in your lawn.

In your planters, one thing, you don't have turf competing. Tree spikes, you don't have to bypass the turf roots. The other thing is that soil is not compacted. Again, you're using a potting mix, right? It's a fluffier, lighter soil. You don't need to break it up with fertilization. I would just get a bunch of those tree spikes and put them in there and use as directed on the container.

Doug: Then another thing you mentioned was mulch. That's something that-- When I'm growing tomatoes in a container, peppers in a container, I'm using straw. For a tree, that's interesting that I wouldn't even think of that in a big container to mulch that, but it makes sense. Mulching the right way.

Lou: Yes, mulching the right way. We've covered in the past the reasons you use mulch. Two of the reasons that you don't really need them in a container, you don't really need mulch, is you don't need to protect it from mechanical damage because you're not mowing. You're not string trimming around the base of the tree. You don't really need it to alleviate compaction and return nutrients. However, where it's really important is that water loss. Containers are exposed. You have to irrigate them. You have to water them frequently. They lose a lot of water because of their exposure.

Putting a layer of mulch on the top of your potting mix there helps retain the soil moisture, helps regulate that soil temperature in heat and in cold, provides that layer of insulation. It also looks nice, right? To have that on there. Yes, and you could use pine bark nuggets, look really good in a container. Those 2- to 4-inch chunks that go on there. Or you can go the opposite direction and get that really super fine, triple shred stuff that just makes it look gorgeous.

Doug: With containers this size, you should really plan it out because once they're filled and once they're planted, they're going to be, for a homeowner, very difficult to move.

Lou: Absolutely. No, this is a permanent spot for the next few years for sure.

Doug: Well, Lou, I never thought about growing trees in a container and now I've got some ideas since I do love that Sugar Tip. I think that's something I'm going to think about putting in my garden, like two at an entryway. Then, I don't know what to use for my filler, but I've got some ideas for the spiller. As always, thanks for your time and great information.

Lou: Doug, it's been my pleasure. Have a great day.

Doug: Tune in every Thursday to the Talking Trees Podcast from the Davey Tree Expert Company. I'm your host, Doug Oster, and do me a big favor, subscribe to the podcast so you'll never miss a show. If you've got an idea for an episode, maybe a comment, you can either send us an email to podcasts@davey.com. That's P-O-D-C-A-S-T-S at D-A-V-E-Y.com. Or you can click on the link at the end of our show notes to text us a fan mail message. Your ideas might be on a future podcast. We'd love to hear from you. As always, we'd like to remind you on the Talking Trees Podcast, trees are the answer.

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