How to Prune an Overgrown Hedge
LESLIE: Are your overgrown shrubs and hedges making your yard look like something out of a Gothic horror movie? Well, you may know you have to trim those hedges but just where do you start?
TOM: Well, the solution is to do some very strategic pruning that will improve the look of your landscape and help hedges heal and thrive. Here to explain how is Roger Cook, the landscape contractor for TV’s This Old House.
ROGER: Can we hedge around the subject?
TOM: So, Roger, I’ve got a story for you. This past summer, my son decided that he was going to help out around the yard.
TOM: So, when I wasn’t home, he grabbed our hedge trimmers and decided that he was going to cut our beautiful Manhattan Euonymus hedges down to the nubs.
ROGER: Uh-oh. Mm-hmm. How’d that work for you?
TOM: Which required some pretty serious emergency steps to keep them alive and help them recover. So, in retrospect, that hedge trimmer really can be quite a dangerous tool in the wrong hands, huh?
ROGER: You know why it’s so dangerous? You don’t get tired using it, so you just go on and on and on.
LESLIE: And it’s fun.
ROGER: The old hedge trimmers? Yeah. But the old hedge trimmers that you had to manually do, after a while you’d stop and stand back …
TOM: Wear you out.
ROGER: Yeah. “Where am I? What am I doing?” These ones, you just keep going and going and going.
TOM: So, what we ended up doing was putting a soaker hose down at the roots, giving it sort of an emergency shot of water and then some Holly-tone to kind of get some fertilizer in there. And they did come back and they look great but for a while …
LESLIE: And you really couldn’t be mad because he was helping.
TOM: No. He was trying to help out and yeah, I didn’t want to discourage him. But for a while, it was looking pretty bad.
ROGER: Well, it’s – a lot of plants will bounce back from what we call a really hard, hard pruning like that. And it’s one of the tools we use when we have a really overgrown hedge. We’ll cut it down really low like that and let it sucker out and grow into a new, lower hedge. But for the most part, you really don’t want to look at that for a long period of time.
TOM: Right. So what’s the best way to really deal with an overgrown hedge? It’s kind of very strategic, isn’t it?
ROGER: Yes. And the tool I love to use is hand pruners. It’s a lot slower but it’s a lot more pinpoint. You know, you’re not just running down cutting every branch; you’re cutting just certain branches so you can shape a plant.
And the key to keeping a good hedge is to keep it green on the inside. If you look at most hedges where the shears have been used, you part the branches a little bit, it’ll be all brown or empty on the inside.
ROGER: There’s no interior growth, so you can’t cut it back. So the first step I do is I will open up small holes in the hedge to allow sunlight to get in the inside.
ROGER: And then it’ll start to sprout out. And then you can go back in Year 2 and cut it back even harder, in Year 3 cut it back harder again and you’ll have a brand new hedge that – no longer 6 feet tall but what could be 3 feet tall.
TOM: So reach down deep with those pruners, take out chunks, so to speak, of that hedge.
ROGER: Yeah. Yep. And the reason …
TOM: But strategically done and then it will sort of close in around those holes that you’re forming.
ROGER: Right. And the reason we’re doing that is we don’t want it to look ugly. And the few holes that you point in – still, overall, it looks like the hedge.
LESLIE: Now, what about the areas where you see the shoots of new growth? Do you want to just take off what you see as the new growth or leave those areas alone?
ROGER: It depends whether you want the hedge to get wider or taller. Obviously, new growth coming from the bottom is going to make the hedge wider. If it’s already in a confined space, then you want to keep it trimmed down.
If it can get wider, then you can use those to grow up and make the plant wider, if you’re just controlling the height and not worry about the width.
LESLIE: Mm-hmm. But if you’re controlling the height, do you just take off the part that’s the new growth or do you go into the hedge a little bit?
ROGER: You take old and new wood. That’s the only way.
ROGER: Because, like I said, once you shear them to a certain height, you can’t reduce them anymore because they get so thick on the end.
ROGER: It grows almost – looks like a hand spread apart. Then you come back the next year, you can’t cut in that close so you come out another inch or two. And it just grows and grows and grows.
With the hand pruners, you can cut off a whole – one stem with all that fan shape on the end. And you’re opening up a hole. The growth will start on the inside. Then next year, you can reduce it even smaller.
TOM: Now, is there a better time of year than others to do this sort of thing? Is it a good thing for the spring?
ROGER: If you’re doing a real hard prune, I like to do it early in the spring before leaf out – before the buds open up. Because you can make big holes and then all of a sudden, the new growth comes out and fills it up.
LESLIE: Fills up.
TOM: Now, what about a sick hedge, one that’s not doing too well? Is there a way to sort of save it with better pruning?
ROGER: Better pruning will help. There’s a number of things you’re going to look at. Is there an insect or something eating at the stem or a bore in the stem, which would make the plant sick? Is there too much mulch around it? Is that the problem? Is it not getting enough water? So, you would use pruning in combination with fertilizing and really looking at the plant to see why especially one or two are dying in the whole hedge row. And also, you want to prevent the whole hedge from dying, so you really want to get in there and figure out what’s going on.
LESLIE: Alright. We’re talking to Roger Cook, the landscape contractor for TV’s This Old House.
Now, Roger, aside from trimming, how often should you really fertilize your hedges? And is this really a similar schedule to what you’re looking at for your lawn or are they completely independent?
ROGER: Totally different. Totally different. The lawn needs much more fertilizer than a hedge should. But the problem you have is if you fertilize a hedge, you’re making new growth, which may make more pruning, more maintenance. So, again, I would recommend you do a soil test on the soil where the hedge is and see what that tells you.
LESLIE: Because that could be different than the soil for your lawn.
ROGER: Exactly. It is definitely different. The lawn will tell you that it needs a lot of nitrogen and the plant will tell you, “I might not need so much nitrogen, because that’s just going to make me push new growth.”
So, take and do a soil test and then add probably an organic to meet the requirements of the soil test. And that’ll just spread out the fertilizing over an extended period of time.
TOM: Great advice. Roger Cook, the landscape contractor on TV’s This Old House, thanks so much for stopping by The Money Pit.
ROGER: Oh, I had a ball.
LESLIE: Alright. You can catch the current season of This Old House and Ask This Old House on PBS. For local listings and step-by-step videos of many common home improvement projects, visit ThisOldHouse.com.
TOM: And This Old House is brought to you by Lumber Liquidators. Lumber Liquidators, hardwood floors for less.