Cutback Trees and Shrubs

Cutback Trees and Shrubs

Part of Ep. 1702 Think Green

At Olbrich Gardens in Madison, Director of Horticulture Jeff Epping shows us how and why some trees and shrubs actually benefit from being cut back to the ground every couple years and explains the basics of cutback pruning technique. At Olbrich Gardens, willows and locusts are good examples of cutback pruning.

Premiere date: Apr 29, 2009

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
You're looking at two coral barbed willows.  Believe it or not, these are the same age, the identical plant, and they were planted at the same time.  However, the one on the right is much taller and has less color.  The one on the left was cut back only about two years ago.  And it has this vibrant gold and red color.  We're going to learn how you can make these willows look the same in your own backyard.  I'm at Olbrich Gardens in Madison, with the Director of Horticulture, Jeff Epping.  Jeff, this is a special pruning technique.

Jeff:
It really is.  It's rather simple, but it's very effective.  We just call it cutback pruning.

Shelley:
Cutback, works for me.

Jeff:
It's what we do.  We just take them to the ground.  And the reason we do that is because we want the maximum coloration on the young twigs.  That's where the color is, on the young growth, not the old.  So this plant, Salix alba Britzensis, or the Coral Barked Willow, wants to be 50 to 60 feet tall.  It's a tree, for sure!  But we don't let it.  We're mean.  We cut it to the ground every four to five years, so you get the effect that you see here.  Lots of stems.

Shelley:
Multi-stem, instead of a single trunk.

Jeff:
Right, which most trees would be.  And we get all that coloration down here, where we can see it.

Shelley:
At eye level.

Jeff:
Not the old, dark bark, like most trees get down low as they age.

Shelley:
And what kind of trees?  You mentioned willow.  What else might we use this with?

Jeff:
We use this cutback technique on Sunburst honey locust.  There's another locust with burgandy foliage.  Those we cut back to keep them more in scale.  They don't have the awesome coloration like this in the winter, but they keep in scale with a perennial border or shrub border.  And so it works out quite well.

Shelley:
So nice for a small landscape.  Come and show me the technique.

Jeff:
Let's do it.

Shelley:
Wow, so even though this willow is the same age as the other one, it's twice the size.

Jeff:
That's right, because it has been cut back four or five years ago, where the other one, it was only a couple years ago.

Shelley:
It grows fast.  It's a fast growing plant.

Jeff:
Absolutely.

Shelley:
I can see as we go down the branches, you know, there isn't the color.  The bark almost looks just like a regular tree.  You've lost all the beautiful reds and golds.

Jeff:
You can see the brownish coloration starting.  You know, just like in any other tree.  So what we want to do then is cut this to the ground.  You can even see, if you look closely, the old stumps before we cut it back the last time.  This is one that we already made a cut on.  Then we'll cut back this guy, and then continue to cut them all back.

Shelley:
So a pruning saw is about all you need to do this, then?

Jeff:
Yeah, absolutely.  It's nice and sharp.

Shelley:
I'm going to step back while you do that.

Jeff:
And willow, thank goodness, is a nice soft wood, as most people know.  So you can get through it relatively quickly.  Make a nice clean cut, and get this out of our way here.  Like I said, we go through and remove all of these, so we get all fresh growth.

Shelley:
Every single one?

Jeff:
Yes, because as most willows are fast growing, this will get six, seven, maybe eight feet tall in one season.

Shelley:
The same year?

Jeff:
And you know, it'll just be a green mass.  The coloration kind of goes away, and your eye will just go to all the beautiful flowers around it.  And then when the leaves fall again, in the autumn that's when you'll notice it again, and you'll have all that color right here.

Shelley:
Right here at eye level, the maximum impact.

Jeff:
Yes.

Shelley:
Wow, I can't wait to see it.  Right now, it looks like it's kind of scary.  You said that this is a good technique to use with curly willow, which is something I have in my yard.  But you've got one over here that looks like a tree.

Jeff:
Yeah, that's beautiful.  It's called Scarlet Curls Willow.  It's a Salix, as well.  So that's about the maximum height, 30 feet.  But you know, it's a big tree.

Shelley:
It's not going to fit for many people.  For some people, it won't.

Jeff:
And I actually have the same plant in my own home garden.  But I only let it get about ten or 12 feet tall, if that.  I cut it to the ground probably about every third year.  So that allows me to keep it, again, beautiful coloration down low.

Shelley:
And the curls.

Jeff:
Yeah, that's a very architectural plant.  So I up-light it with landscape lighting, so I can enjoy it to its fullest all winter long, as well.

Shelley:
You've got one other.  It's a slightly different cutback technique that you use on another plant.  Let's go look at that.

Jeff:
All right, let's do it.  Shelley, this is the other plant that we had talked about.  This is the Golden Southern Catalpa.

Shelley:
Aren't they usually a huge big tree?  They do get very large.  But this one, we don't want that to happen.  We cut it back very hard each season, but not to the ground, like we did with the willow.  This, we're just cutting the tips back.  We're heading it back, as we often call it.  So you can see many of the locations where it was cut back to last season.  It grows up to three feet, maybe even four feet tall.

Shelley:
So this is all new growth.

Jeff:
All growth from last season.  You can see it's not branched.

Shelley:
You get that because of cutting it back so much?  Does it stimulate the growth?

Jeff:
Absolutely.  And it's very well branched because of that.  If we were going to cut back this one, which we would, we'd cut just like in a location like this.  We're saving a couple nodes.  Nodes are visible, because there are bud scars from the leaves from last year.  You can see those.  We know there's a bud just above that, so we cut back to just above that location Then, that'll throw probably two, maybe even three new shoots off of that.  So we'll go around the entire plant.  The first thing we want to remove, though, is dead wood.  You can just tell by the sound of it that it's dead, and another one here, or any broken branches that might occur.

Shelley:
Regardless of what kind of tree you plant, you want to clean up that kind of stuff.

Jeff:
Those are always the first things to get rid of, absolutely.
Shelley:
So what's this going to look like in August?

Jeff:
In August, it will be full of beautiful golden foliage.

Shelley:
Gorgeous, I can't wait to see it.  Thanks, Jeff.

Jeff:
You're welcome.

Shelley:
If you'd like to learn more about any of the places we visited today, or any of the topics we discussed, please visit our Web site at: wpt.org/garden I'm Shelley Ryan.  Thanks for watching on the Wisconsin Gardener.

EPISODE SEGMENTS+
EPISODE RESOURCES+

Buy DVD »

Funding for The Wisconsin Gardener is provided, in part, by The Wisconsin Master Gardener Association.