 You know, now, right now is a great time to prune many other shrubs in your landscape. And to find out the best way to do it, we've got Joe Zulezik here, our Extension Forester from North Dakota State University. So let's welcome Joe to the forum. It's on. Got me? Okay. Well, thank you everybody here for that lovely welcome. Good to see everybody online tonight. Actually, no, I can't see you, but glad you're joining us tonight. Today we're going to talk about prune shrubs. And as I was developing this presentation, I was thinking about this, how to develop it, and why do we even prune shrubs? You know, why do we do this? Same reason we prune trees. The goal or the goals are to control size, control the shape, control the density of those shrubs. Same thing with trees. Now, the thing is, they're all related. I'm trying to put this together. You put in different techniques here. Talk about size or shape. And all three are related. So this actually is going to bounce around a little bit. And it might not flow as well as we would hope. I just want to give you a heads up on that. The picture here on the screen, that is the NDSU Horticulture Gardens. This is several years ago. The flowering shrubs there, Juneberries, so early spring, looking beautiful. But then there's some, in the foreground, you can see there's some shrubs that are gone. What happened there? Those were dogwoods, and I cut them down to the ground. And yeah, they came right back. It wasn't a big deal. And we'll talk about that a little more. So that being said, we're actually going to start with trees. Just to give a couple examples and to talk a little bit about the terminology that we're going to use. I don't get hung up on terms, but sometimes when we're trying to communicate, what one person says is not what the other person hears. I mean, married folks out there will agree with me. So let's just talk about what terms we're discussing here. Yes, I am married. I don't think my wife's watching tonight. Okay. In terms of pruning trees, this is what I call a removal cut. Usually it's called a thinning cut. We're removing the smaller branch from the bigger stem. And it's very common. That's what we usually use. I call it a thinning cut. Oh. There's another type of cut where we're actually cutting the bigger part. It's called a reduction cut. It's not very common. You'd see this in deciduous trees only. You won't see this in conifers. At least you shouldn't. It is uncommon, but it's certainly acceptable. What we try to have is that branch off to the side has to be about half the size of the main stem or bigger. Why would we want to even do that? Why do we want to reduce this tree? Actually, often what we're trying to do is slow it down. Slow down its growth. We will do this probably on one of the branches, not so much on the leader. Although I have seen this done sometimes with apple trees, we're trying to create a more open form. Trying to actually remove the central leader, which if you're trying to create a more open form, that can be done. Anyway, not very common. And Tom's much more of an expert on apples than I am. He's pruned a lot more apples than I am. than I have. Excuse me. Heading cuts are not recommended for trees. Whether they're deciduous trees or conifers, period. Heading cut is just kind of in the middle of a branch, in the middle of a stem, not near any connection or conjunction. This is not recommended for trees, period. However, with deciduous shrubs, well, we're not so much worried about that. So let's go back to this thinning cut. And let's apply this now to shrubs. What happens here? Actually, we're going to just do an example of trees, and then we'll go to the shrubs. Let's remove these two branches with thinning cuts. We're keeping the main stem. We're keeping a bunch of the other branches. What happens is that tree is thinned out. The canopy, the crown of that is opened up. We might want to do that if we're developing structure in a tree. Again, those shrubs are a little different. But regardless, it's opened up. That's what we're trying to point out here. How about thinning a shrub? When we're thinning shrubs, the goal is really to maintain the size of the shrub. It's not going to get bigger. We're not knocking it back completely. We want to maintain size. So in this example, we're starting here with this shrub. It's an interesting shrub. It comes from the ground apparently. In this example, we're actually going to remove about a third of the stems all the way to the ground line. I said all the way to the ground, four to six inches. It doesn't have to be perfect. We're actually going to use heading cuts on roughly a third of the stems or the branches. The goal, excuse me, the goal eventually is to maintain the size. Remember, heading cuts are okay on deciduous shrubs. You can cut those in the middle of a branch and it's okay. Why is it okay? I'm trying to engage the audience, but it's hard to do because we're online as well. Why is it okay on shrubs and not trees? The reason is because heading cuts result in sprouts. A lot of sprouts. Sometimes reduction cuts will, too, if they're too heavy a cut. But heading cuts result in sprouts. On a tree, those sprouts aren't very strongly attached. There's a lot of other problems with heading cuts on trees. On trees, we're worried about those new branches eventually breaking off and falling on us. We're not so worried about that in shrubs. We can head back shrubs. And in the end, after we follow this regime, thin out about a third of them, cut back about a third of them, we have this thin shrub. And it will grow back and it will maintain the size overall. And this is actually fairly common. Now, admittedly with myself, my own experiences, I usually just let things go. But this can be done. Remember those reduction cuts. We're cutting the larger branch for the larger stem. And the smaller one should be at least half the size of the bigger one. Okay, and deciduous trees in moderation. What about deciduous shrubs? Well, let's look at that. Now, in this example, I find it interesting. We'll talk about this a little more. It's a lot of diagrams. I apologize for that. I don't have great pictures. So we'll do the best we can. So we're going to start here. Let's use reduction cuts. We're going to leave some of the smaller stems, cut back some of the bigger stems. And when we're done, this is what it looks like. Okay, roughly the shape is round, not perfectly round, not nice and even, but roughly the shape is round. And when it comes back, new growth, that we still have that rounded shape, but it still maintains the form a little bit, but it also is smaller. The goal in reduction is reduce. Make it smaller. We want to try to more or less keep the same shape. Now, that being said, we're using reduction cuts. Okay, what if we're using heading cuts? What's going to happen then? Well, in that case, start with the same shrub. Heading cuts, basically, we're creating a hedge here. We're cutting at a specific distance, specific location, whether there's a branch union there or not. Okay, there's heading cuts. There's probably actually heading and reduction and thinning, because we're actually just shaping the whole thing. And when it's all done, it looks like this. And sometimes with those heading cuts, the spouse will come back and try to be more leaders. They'll try to grow straight up. So that can cause a little problem sometimes. You would definitely see this in trees. I've often heard people say, when they're topping trees like this, when they're using heading cuts on trees, oh, we're just giving the tree a haircut. Sorry, trees don't have hair. They have branches and leaves. Those leaves are where they get their energy. That's how they produce energy from the sun. That's how they produce sugar, and that's how they grow. Again, I'm not so much worried about that on a shrub. Yeah, shrubs will grow back, and quite frankly, they've got some mechanisms where we can just plain start over. Another technique, it's called renewal. At least this is our own word for it by a predecessor, Esther's predecessor, excuse me. Ron Smith uses this term, renewal, where you're starting off with a shrub and you're removing about a third of the stems all the way to the ground. And you let those grow back. And as they grow back, they're going to develop, you're actually removing the oldest ones. You're removing the really oldest ones. Letting new spouts come along. Again, you remove about a third. Let those new spouts come along. And over the course of two to three years, you do this two or three times, and eventually you have a brand new shrub. This is acceptable. I've never done it quite like this. I've come close, but this is a really easy way to get that shrub started over again. Similarly, again, this terminology, there's a lot of these that kind of blend one to the next. Similarly, there's this technique called coppicing. And sometimes we use this in forestry. Sometimes it's called rejuvenation. We're making it juvenile again. We're making it young again. I've also heard the term renovation. And in my pruning book by Dr. Ed Yeoman, the 300-plus pages, he actually says remote. And I think he's trying to... I think it was a typo. I think he meant renovate. It was kind of bizarre. Well, what's the deal here? Well, basically, okay, this example, the background here, you see red owes your dogwood. Great shrub. One of my favorites. Here's some red owes your dogwoods in Bismarck. And these things are about eight to 10 feet tall. They're really long and leggy. And what the guy did is he cut them down to the ground four to six inches. He was in his mid-fifties. He needed to work out one winter day, one March day. I know what I'll do. I'll renovate those shrubs. I'll rejuvenate them. Good for him. Good for you. His name's... No, I shouldn't name names. Sorry. Never mind. Okay. Anyway, he cut them down to the ground. Okay, about four to six inches. It wasn't exactly perfect, but about that high. What happened? By the end of that first summer, they were about two-thirds of their original height. They just started right over. And let me tell you, dogwoods do great at this. Willows do great at this. Okay. A lot, a lot of deciduous shrubs will do great at this. Now, in this, if you happen to see... It must be like July or August, because all his grass is brown at this point. But by the end of that first summer, they grew back. Okay, to two-thirds of their original height. They're doing fine. Now, I do want to point out... Okay, they had good color. But I do want to point out this is deciduous shrubs only. This is not conifers. Dormant season only. Mostly. We'll talk about that in a moment. With these... We did this in the dormant season. Right now is a great time. Want a good workout? Go and cut down shrubs. Probably not every year. Okay. The shrub has to rebuild its energy reserves. It has to rebuild its nutrition. It's got to rebuild the stomach. It's got to rebuild leaves. It's got to rebuild buds. It has to rebuild that. And that's kind of important. So, in this case, I've heard of as little as three years, accomplishing a three-year cycle. I'd say at least five years. You know, maybe every five years, maybe every eight years, whatever. You can do this quite a bit, actually. Now, that being said, unhealthy or very old plants may not respond. So, you've got to be a little careful. When I did that processing and that windbreak at the Hort Gardens, there were some shrubs that didn't come back. I have them planted in a nice neat row and generally where there was a gap, well, the side ones just grew in. They out-competed anything that was going to come back anyway. So, it wasn't a big deal. It filled in just fine. But be aware that if the plant is unhealthy or it's really old when you start this, it might not respond. So, be careful about that. Okay. Now, that's controlling size. And let's talk about controlling shape very quickly. And what are we being here? Well, of course, there are hedges, really formal hedges like these. I can't imagine a hedge that tall. Can you? I cannot. Topiary and bonsai. And we're not going to talk about topiary or bonsai. Okay. We're going to talk about hedges. In terms of hedges and controlling shape, you can have a nice formal hedge like this where it's sheared and very briefly try to make the bottom wider than the top to get a little sunlight down there. Hedges are a little difficult because they're always getting bigger. They're always growing. And controlling that is very difficult in a formal hedge like that. Now, when the new growth comes along, sorry, I forgot to put this in, when the new growth comes along in the spring and it's about anywhere from six to 12 inches tall when it's still green and tender, that's when you should shear the hedge. Okay. You shear it to about within one to two inches of the old growth. What I've, the plant we had the hedge with was Katoniaaster, made a nice thick hedge, had some other issues with insects, but as far as the hedge goes, generally it did pretty good. And if the hedge gets too big, if it's deciduous, you can always cop this and start over. That's kind of anything about it. Again, try to get the bottom really wide and then build it up from there. Or you can try an informal hedge. An informal hedge, you know, you have the plants planted together nice and close like you would in a regular hedge in a formal hedge, but it's less formal. It's informal. It's not square shapes, not geometric shapes. Okay. What happens if you try this and the plants are all next to each other? For this example, we've got a nice tall hedge here. It's getting long. So we try a bunch of reduction cuts and what happens is it brings that hedge down into something a little more manageable. It's less, it's not formal. It's a little more, I don't know, informal. Civilized. It's more natural looking, yes. And it's funny. They talk about one of the advantages of an informal hedge is if somebody falls through or gets broken down, it's hard to tell. You know, that happens in a formal hedge. You get a hole in it. You get a gap in it. It's pretty easy to tell. This is harder to tell. So very quickly, I want to talk about pinching. Pinching in terms of cutting new growth in the spring when that comes out or clipping. You can do it. You don't have to pinch. You can actually use clippers. But this is a way to increase density. Again, to say to a shrubs, you're heading into this year's growth, the most recent year's growth. Okay. And that should, in the long run, make it fuller and thicker. That being said, now we're going to talk about some of the finer points. In all of this, I was talking about, I was talking about this. I mentioned nothing about flowers. Flowers are a big deal to a lot of people on a lot of shrubs. Okay. And if you want flowers to come back, well, then timing is important. If you want flowers to come back, you prune just after flowering on all these different ones. I get questions every year, especially on lilacs, you know, that, okay, we want to prune our lilacs. If we prune right now in March, or in the spring season, will we still get flowers? No. No. The flower buds are on last year's growth. This year's flower buds are on last year's growth. So if you cut off last year's growth, you're going to lose this year's flower buds. So after flowering's done, then you trim, you pinch back, you prune before next year's flower buds are even built. And this goes for a lot of different species. I kind of have hydrangea in my collection mark here. I don't have experience with pruning that back. Basically, we have a hard time keeping hydrangeas alive. You know, they die back, at least ours do. And we'll probably post that question out there when we interact a little more. But these are the most common ones. We'll see it around here. Yes, there are even more that we have to worry about outside of North Dakota, more species like this. So just after flowering on all of these. And oh, yeah, and then there was if I grow in Barbary as a flowering shrub for the flowers, I got nothing here in Tardo. Barbary is sharp, it's pointy. That's how I know it. It's got some pretty leaves. I've never really seen it flower. I think they said caragana, Siberian pea shrub. The flowers, have they grown that for flowers? Yeah, one. Okay. Just to be, yeah. Thanks. All right. You know, macarons. We got that, pears and cherries. We got those. Those are beautiful. So prune those after they flower. Very briefly, because we're running out of time here. This is about perfect conifers. I'm not going to get in too hardly because conifers are tricky because each one of them is a little different than the others. And all I have to say right now, we will do this next year for a presentation. Conifers, you can use thinning cuts anytime of year. Okay. That's fine. They're most anytime of year. We don't use heading cuts on conifers. Pinching conifers is really tricky other than, well, yeah. It's really tricky and I have her don't do. Maybe we'll get into this next year. It's really tricky because of where the buds are. On some species, the buds are all over the bud. The buds are all over the branch and it really doesn't matter where when you prune or pinch, some they form only at the end. So you got to be careful about those and we'll get into that presentation next year. With that being said, I finished early. You said you'd give me a hug. Tom said he'd give me a hug. So you said you'd give me a hug if I finished early. That's the second talk. Okay. So that being said, I'll open it up for questions and I'll go to our moderator here. Okay, Joe. How about how far back can I prune a spirea bush? How far back can you prune a spirea bush? My question, do I have to repeat the question? No. Your mic? Yeah. Okay. If you want clarification, I'll be happy to. For example, are we talking about pink flowering, spirea, or the bridal reed spirea? I will defer to you, Tom. You guys, I think you might have experience with this. Yes. Okay. If they're talking about bridal reed spirea, those are the ones with those white, gorgeous flowers that cascade in the springtime. That forms its buds on the previous year's growth, the flower buds on the previous year's growth. So just like Joe was talking about with lilacs and such, that in many cases, what we do is we wait until those plants have bloomed and then we go after them. And we will do the rejuvenation type of pruning where we will cut back the old canes right down to the base. It's just a selective pruning, maybe 25% of these. Kind of like a thinning. A thinning. Right. It's a base. If it's a pink flower, spirea bush, they're very common. That blooms on its new wood. And so now is a good time to prune those back about halfway. And then that will keep them compact. And then the new flush of growth will give you a nice bloom this year. And then also after the first flush of blooms, you cannot trim off those wasted pink flowers. And sometimes you get a sudden bloom and sometimes you get a second flush of blooms. So make sure you know your spirea. The pink flower ones are more common today. Cut them back halfway now and you'll be delighted this summer. Of course, the first question is one of the trick questions. Yeah, spireas are tricky. It depends. Okay, Joe. How about those lilacs? You did a good job discussing about lilacs in general. But how about something particular? Like, should I clip off the seed pods? That's awesome. You can. You don't have to. Seed pods are the previous flowers. Okay. At that point, they are taking energy from the plant. Some people don't like how they look. Some people do like how they look. They add a little bit of interest. So it really could go either way with those. How about you mentioned dogwood. Now we're trying to prune verigated dogwood. Yes, it is. My experience is yes, it is. That being said, the verigated dogwoods, I assume most commonly ivory halo dogwood around here, it's a beautiful shrub. I've seen some really nice ones. I've also seen some really lousy ones. I think it's very site dependent on how well it grows. Okay. If it's, again, as I pointed out, with that coppicing, be careful in terms of if it's unhealthy or really, really old, it might not respond. So it's going to depend on the individual plant. Okay. Back to lilacs. There's a very large lilac in their backyard. Should they prune that after flowering? If so, should they cut it all the way down? You know, don't cut it all the way down after flowering. It's a little tricky here. If you want to prune and just prune and shape and thin out, you could do that after flowering and you'll still get flowers next year. If you want to rejuvenate the whole thing, you would do that now. You'd cut it down to the ground now, but that being said, you won't get flowers this year because the plant has to put its energy into new growth. I don't recommend cutting it down to the ground after that first flush of new growth because it spends a lot of energy putting out new growth, new branches, new leaves, and if we then cut it all down to the ground, it's got to put out a second flush and that's a real hit on the energy reserves of a plant. They store energy for the winter and they can take a little bit of hit after the leaves come out. I think about this in terms of insects. Defoliating insects, the leaves are coming out, the defoliating insects come in, they chew off all the leaves. Is that hard on a tree? Yeah, because it has to put out second flush of leaves. Can it do it? Generally, yeah. Usually it can. Usually there's enough food reserves for it to start again but do that two or three times is tough. Sorry, I'm going on a little too much. It's good, Joel. It's really good. Lots of good questions coming from the people. I'm keeping in common. This person has a coletal spruce and the center branch appears to be dead. I guess we call that the trunk or the top of the tree leader. The leader. The rest of the tree looks great. Should they snip off the leader? If the leader is dead, yes. What you can then do is take one of the side branches near the top, you can bend it upwards and squint it in place such that it will become the new leader. You can do nothing. You can do nothing and that will likely happen on its own or you can zip it up and help it along its way. It's a little tough to do sometimes, but you can do that. Lots of lilac questions here. How about how many leaves after you cut a lilac to the ground can you expect flowers again? I don't know. That's a good question. I would expect them in the second year if there's enough energy reserves. It depends on growth. At least with trees, we talk about trees have to be certain size before they flower. It's not an age thing. It's actually a size thing. With shrubs, it's kind of similar. In terms of new growth, the tree, the shrub, the lilac has to rebuild new growth above ground and that takes energy. It's still got an established root system though and that's a good thing. It doesn't have to establish roots and the top. It just has to establish a new top. So I would expect pretty quick, two to three years. How about my poor lilac hasn't bloomed for years? What can I do, Joe? Will rejuvenation really help? That's a good question. I don't know. My guess though is that it's over top and not getting enough sun. That's probably what's going on. So look at the environment and if you get it more sunlight, that's probably what's going on. That's a good problem. Make sure it's a lilac. I have a tree that's 35 years old that overhangs my deck and I've been cutting the branches so it is a semi-circle. So the birds cannot sit right above the deck. Okay. Is that okay? Can I keep doing that? Everything is fine. I recommend those thinning cuts. You can use reduction cuts. You can shape a tree. That's fine. With trees, I do want to say generally we recommend don't take off more than about one quarter of the branches or leaves in any one year because more than that it really starts to stress the tree a lot. Yeah, if you take off more than that can the tree survive? Sure. I would suggest the more you go above that 25%. We used to say 33% and that was a little too much and the recommendation now is back down to about 25%. Okay, back to spring flowering shrubs. How long can we leave flowers before we prune them so we can enjoy the flowers? I'd say leave them on as long as you can. Generally blooms in North Dakota Oh boy, it depends on the species. Anybody ever get more than about two weeks out of a shrub? Yeah, it depends on the weather, especially the wind. So I'd say let it go through its flowering time and then take them off. Is it possible just to selectively prune your lilac to take out a few of the the teens at the base in March or April? Absolutely, it's certainly possible. What I've often seen with lilacs are a few really big stems and a lot of little suckers coming up a lot of thin suckers coming up. Yeah, you could thin back those larger stems take out about a third of those and let those young ones develop. And if you took out a third of the bigger ones you're still going to have some nice flowers and a nice shrub overall. One thing we really didn't talk about is the shape of plants and what you envision this is going to be and try to look with the artist's eye as I like to say. Try to look with the artist's eye to see what's just going to look like if I cut here. What is going to be lost? Where is it going to come back and fill in? It's just kind of hard to do. It's a little tricky. It takes a little practice. My wife is an artist so she's taught me a lot of these things. Well, how about, how can I stop my apple tree from getting too tall? How can you stop your apple tree from getting too tall? I don't want to head it back. You don't want to head it back. You can use those reduction cuts and reduction is different from heading. You are removing a central leader and you're developing a more open form. Tom, do you have a presentation about apple tree pruning? I'm sorry to put you on the spot like this. It's a little tricky because it's as tricky as you want it to be but you can use that reduction cut on the main leader and then you just grow a more open form. I think that's a good way to put it. I would say the only way to do that without heading back is to make the single cut method which is what I call a chainsaw at the trunk and cut it all down and replant a semi dwarf tree in place. That's one way to do it too. That's the only way I know how to do it without heading it back. Otherwise, I like your idea if you've got a big old tree to head it back like you said, you've got to head it back. You've got to cut out the main trunk and now instead of a central leader Christmas tree it's going to be more like an open umbrella tree. That's okay. There's nothing wrong with that. A lot of old orchards like I'm from, that's the way we prune our trees. The whole key for good apple production is to get lots of light in the canopy and there's no sin cutting down the trees so it's manageable. It is tough because trees want to grow up. Even those dwarf ones do, just that there's limits on it. It is tough. We've got a doggle crab apple right now that I'm trying to develop good structure on and it's got that big central leader. It's growing really great and it's going to overgrow the house if I don't control that. Sorry, back to you Tom. Okay Joe, we've got a very destructive question here. What's the best way to kill a shrub that you don't want? Is pruning the best way? Cut it down to the ground, coppice. Actually wait a couple more weeks until it's just starting to flush out. Cut it down to the ground and spray it with herbicide. Glyphosate, Roundup should do a pretty good job of that. Okay, there you go. Kill the shrub. No more pruning needed. How about let's talk dogwood. They have some old growth that's dying or dead. We want to keep them looking good. Do we cut out the dead material? Yes, absolutely. You can cut out dead material almost any time of year and I'd highly recommend it. It's just a haven for diseases. Do you ever time when pruning feeler should be used? I would give the easy answer and say mostly no. The easy answer is no. The harder answer is mostly no. There are certain diseases that we don't have here in North Dakota where it can help prevent disease from getting in but we don't have those in North Dakota. So don't use a pruning feeler. You're wasting your money. Any other questions? Okay, what does it take to get virgin pear trees to bloom more? Okay, I don't know. We're kind of getting off pruning here. Yeah. Virgin pear trees? Wow. I'm familiar with that. Like I said, it must be young pear. How about the patience? Yeah, trees have to be big enough to flower. Not an age thing, it's a size thing. And if they haven't been there long enough, they're not big enough, they're not going to flower. I'm sure you get questions every year about honey crisp apple which takes a long time up here anyway for it to get big enough or before it flowers. People say, oh, I've had this in the ground for years. It doesn't flower. Well, it takes time. That's notoriously slow to reach size. Yeah, and I like your idea also, Joe, about make sure it's getting full sun. That makes a big difference. Was it time? There's so much good stuff here. How about... Do you want to talk about Honeyberry Plants? I know almost nothing about Honeyberry Plants. Same with me and everybody else here. If you want to know about Honeyberry Plants, I strongly recommend you contact Kathy Weederholt at Carrington. Also, you can download Kathy's talk from last week. She talks about pruning and how it's still a mystery for us on Honeyberries. We don't know how to do it, but the University of Saskatchewan does have a growers guide for Honeyberries. They call those plants a half cap up there, so you can Google that. A half cap production guide from the University of Saskatchewan. Likewise, there's a question about raspberries. I recommend that we... That's kind of a detailed answer. I recommend the University of Wisconsin has outstanding fruit-growing publications for gardeners. I recommend you Google growing raspberries in Wisconsin. You all love the drawings and all the information you need for that. One last question here. How about for an evergreen tree, should we cut off the branches near the bottom of the tree to allow for clearance of mowing and such? If you want to, yes, there's nothing wrong with that. It's not going to hurt the tree. Some people hate it. They say it reduces the structure... not the structure, it reduces the visual quality of the tree. They want to see a nice cone going all the way to the ground. Some people don't. Some people want to see actually that main stem and that cone above it. It's certainly not going to hurt the tree and whoever's running the mower is probably going to be grateful. Okay. That's it for this session. Let's all thank Joe for wonderful talk.