Find out how to transplant a large tree. Get tips on site selection, soil testing, digging, trunk orientation and time of year. Also learn what tools to use to make the job easier.
LESLIE: Well, a yard with well-established shade trees is a great way to enjoy outdoor living. But if you’re starting with saplings, it can actually take a generation or more for your trees to reach full bloom.
TOM: Ah, yes. But you can speed up the process by transplanting large trees that might already be growing on your property or elsewhere. But as you can imagine, this kind of job takes very careful planning and some expert advice. Here to tell us exactly how to do that is an expert: Roger Cook , the landscaping expert for TV’s This Old House .
ROGER: Hey, Tom, Leslie. Thanks for having me.
TOM: Our pleasure. Now, walk us through this. When you transplant  a mature tree, when would you want to do that, as opposed to a sapling?
ROGER: All depends on variety. You know, certain trees can be transplanted spring; some can be transplanted spring and fall.
TOM: So, Roger, walk us through this. When would you want to transplant a mature tree, as opposed to using a sapling? Is it a matter of timing and how long you have to wait to kind of get the effect that you’re looking for?
ROGER: It’s all about time, Tom. You’re buying years and years and years by moving a mature tree. A sapling, you put in, you have to take care of it, invest in it a long time before it gets to be a mature tree.
TOM: Are there some trees that do better moving, when you move them, than others?
ROGER: There are. There are certain species that we call hazards when you move and you want to be aware of them: certain trees that don’t have a really good root system that you would shy away from.
ROGER: Most trees, though, for the – will move very well, even as a mature tree.
LESLIE: Is there a height limitation? I imagine – when I hear “mature tree,” I’m thinking a gigantor maple that’s lining a street.
ROGER: Yeah. We’ve moved trees up to 30 or 40 feet tall.
LESLIE: How big is the root ball on something like that?
ROGER: Huge. In most cases, we use a 90-inch tree spade for a big tree like that so that the spade opens up, goes around the tree and its 90-inch root ball. And then those blades go down into the ground, lift up the tree and bring it to the site.
LESLIE: That’s huge.
TOM: Oh, wow. So there’s a big piece of hydraulic equipment that digs that out.
ROGER: That’s right.
LESLIE: Well, yeah. I mean we’re not picking that up.
TOM: Really. Now, let’s talk about the tree orientation. I would imagine trees get used to growing in a certain compass direction. Do you mark the tree so that it’s still facing the same way after you transplant it?
ROGER: It depends on the variety of the tree. Some trees, like a cherry, have very thin bark and you want to keep it situated the same way.
ROGER: Sometimes with trees, though, I’ll look at the face of the tree and that’ll determine how I plant it. It may not be the same orientation but I want to put the best side of the tree towards the house, where people are going to see it.
LESLIE: Now, is there a certain timing? Do you take this tree out of the ground and go immediately to the new hole or do you have to sort of let it wait?
ROGER: No, no, no, no. The sooner we get it transplanted in and watered, the better off it is for the tree. Usually, on site is great. If you’re in someone’s yard, you’re moving it 100 feet, 200 feet within an hour, it’s going from one place to another. Otherwise, we dig it in the morning, we drive over the road with it and then we put it in that afternoon.
TOM: We’re talking to Roger Cook, the landscaping expert from TV’s This Old House.
Now, Roger, we were talking about transporting large trees. What about some smaller ones that maybe you just want to shift around your property: take one from the back, put it in the front? Obviously, it can be a do-it-yourself project. The key, though, is the digging of the root ball, as in – how do you do that and how do you avoid damaging what’s there?
ROGER: The formula we use is 10 to 12 inches of root ball per inch caliper of the tree. If you have a tree that’s 3 inches in caliper, then you want to have a 30- to 36-inch root ball.
TOM: Got it.
ROGER: So that means you measure out, make a circle and dig outside that.
Now, when you’re digging, you don’t want to rip the roots with your shovel. You want to take a pair of old hand pruners or loppers and cut them clean, because it’ll heal better that way.
TOM: And go straight down and not in an angle, too, right?
ROGER: No. Usually we dig straight down until we find the area where the roots have stopped growing. Then it’s decision time. You can either ball and burlap a tree, which means wrapping it with burlap and then putting twine on and making a big net to hold all those roots together.
LESLIE: Do you plant that in the ground: all the burlap and the rope?
ROGER: Take it off when you get to the new hole but you need something to hold it together when you get …
TOM: In the meanwhile.
ROGER: Yeah. So, what I do, too, is – we have a Bobcat that has forks on the front. We drive right in under the plant once it’s dug. We lift it up, back up and put it in the new hole without bothering with the burlap.
There’s a new way out. It sort of reverts back to what we did years ago. When I first started in the business, we’d go in the woods and pull red maples out of the woods in the spring and just stick them in the ground and they’d grow like crazy, because you’d get all the roots out with them.
TOM: Now, Roger, are there any tools that make this job easier? I mean it sounds like it’s just an awful lot of work.
ROGER: In the last couple of years, we’ve done some work using what’s called an air spade. That’s a gun you connect to a compressor.
ROGER: And you go over to the tree and you start blowing all the dirt off the root system and you keep progressing outside until you get all the roots exposed.
TOM: Wow. So there’s no dirt left.
ROGER: No dirt left but all the roots. You end up taking 99.9 percent of the roots and you lift that tree out of the ground and then you transplant it.
LESLIE: You really have to have a wide-open space that you’re taking it to without disrupting surrounding plantings.
ROGER: Right. Because you need room. That root mass may extend out 8-, 10- or even 12-feet wide. So you really need space to work.
TOM: But it would seem that you’d be giving that tree a really great chance of survival in the future, because you’re essentially going to replace all of that soil you took out with the perfect mix.
ROGER: With the perfect soil and the perfect place and all the roots in place, it’ll just grab and go very quickly.
TOM: Great advice. Roger Cook from TV’s This Old House, thanks so much for stopping by The Money Pit.
ROGER: You’re welcome.
TOM: And for more tips just like that, you can visit ThisOldHouse.com.
LESLIE: And you can watch Roger and the entire This Old House team on This Old House and Ask This Old House on your local PBS station.
TOM: And This Old House and Ask This Old House are brought to you by GMC. GMC, we are professional grade.