THEY’RE THE garden’s biggest residents, relative space-hogs who also dictate a lot of what goes on with the patterns of light and shade. I’m talking about trees. Ken Druse and I named some names of favorites, our desert-island trees, if you will—the ones we can’t imagine gardening without.
You probably knew it when you heard us try to narrow down our lists of desert-island shrubs a month or two ago on the podcast, that trees would be next. Special ones, like Ken’s ‘Morioka Weeping’ katsura, above.
You all know Ken, great gardener, great friend of many years, and author and photographer of 20 great gardening books.
Plus: Just for fun, I’m going to give away a copy of “A Way to Garden,” my 2019 book. Enter the giveaway by commenting in the box at the bottom of the page.
Read along as you listen to the December 28, 2020 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify or Stitcher (and browse my archive of podcasts here).
trees to love, with ken druse
Margaret Roach: Shrubs versus trees: We did shrubs last time, both are woody plants, they’re a little bit different, but there’s not this precise difference. It has more to do with, it has a trunk a certain amount of the way up before it branches out into other stems. Is that the idea of tree versus shrub?
Ken Druse: Versus shrub, sure. It can be [broadleaf] evergreen, or it can be needled evergreen, or it could be deciduous, losing its leaves in the Fall.
Margaret: Yeah. I have two trees among my favorite trees that are shrubs. [Laughter.] Oh, well, never mind-
Ken: [Laughter.] I know just what you mean.
Margaret: …sorry, I just screwed the whole thing up. The native Eastern white pine, Pinus strobus, there’s a selection, or whatever, called Pinus strobus ‘Nana,’ or small. It’s a dwarf white pine. I planted them 30 years ago. I have a couple of them. Now they’re like giant bonsai. It’s the tree, but it’s in a small form. Is it a shrub, is it a tree? [Laughter.]
Ken: Well, does it still start with a single stem, down at the bottom?
Ken: So, I guess it’s a dwarf tree.
Margaret: Yeah, and then similarly, came in the mail 25 years ago or more probably, tiny, tiny little thing, a grafted thing, a cutting. It’s a Cornus kousa, whose name is ‘Lustgarten Weeping,’ named for the nurseryman on Long Island, Baier Lustgarten, who introduced it. It’s small, it’s 5 feet tall, and 9 or 10 feet across. It’s like a mound [above], but it’s a Cornus kousa; it’s a tree, but it’s not a tree. [Laughter.] Oh, sorry.
Ken: I think we just accept dwarf and weeping trees as trees. We include giant sequoias as trees [laughter]. I guess there’s quite a range, but they do have the single stem in common.
Margaret: Indeed. Where do you want to start? I mean what’s a favorite?
Ken: Oh, my gosh.
Margaret: I know; you’re a tree man.
Ken: You mentioned so many things. I was thinking of what makes a tree a favorite? I started making a list. Its health, its oddity, its uniqueness, its history, its color, its shape, its bark, its leaf or needles, its uses, its design uses. Stop me.
Margaret: Stop that!
Ken: We just love them. You mentioned something about… I don’t know if you said grafting. Most of the trees that we buy that are unusual, are grafted to an understock that is the same species but not odd, or not different.
But a lot of trees are grown from seed. I have some very unusual trees that, finally, after eight years, have flower buds all over them, and I’ll find out what happens to them. And they are favorites, if they indeed perform correctly.
And sometimes you can start trees from cuttings, but it’s a little bit difficult to start trees from cuttings, because plants that are mature don’t easily root, and trees—that’s another characteristic, they’re generally mature. They have bark and they’re flowering, they’re grown up. But I was at Cornell and I saw that they were taking oak trees and cutting them down to about 12 inches, and then they’d push up all these soft sprouts, and they made cuttings of them and rooted them.
Margaret: So, it’s young tissue from an old tree.
Ken: Soft young tissue, that was a surprise. O.K., favorites: I’ll do one, you do one, I know you-
Margaret: Just go for it.
Ken: Liquidambar ‘Slender Silhouette,’ and you know I have about eight of them.
Margaret: What is Liquidambar? Give us the English.
Ken: I think it’s sweet gum. Is that what it is?
Ken: Usually, it has those sharp gumballs with prickers. ‘Slender Silhouette’ is sterile, or male—I’m not sure. It was found as a mutation and it’s really, really slender. I’ve got one that’s probably about 40 feet tall, and maybe 2 feet wide [above, at Ken’s garden].
Ken: It’s unbelievably narrow, and I like stuff like that.
Margaret: I was going to say, we’ve had whole conversations about your thing for columnar, or fastigiate, mostly woody plants. And so we can link to that, as well, for more ideas in that vein from boxwoods to trees.
Ken: I like the way they look, but I also get to have a lot more plants because they don’t take up much room.
Margaret: [Laughter.] Yeah, sardines. You want to tell another one?
Ken: Oh, all right. Unless you want to-
Margaret: No, go for it.
Ken: There’s so many. How about dawn redwood?
Margaret: Oh, yes, yes, yes. The Metasequoia glyptostroboides, is that correct?
Ken: Oh, well yeah. You could say it. [Laughter.]
Margaret: Well, I don’t know, I just made it up.
Ken: That’s true. And I think we’ve told the story before when we were chatting of how maybe it’s for the dawn of time that it got the name, and it also has nice fall color. It’s a deciduous conifer. So it has needles, but they drop in the fall, they turn color, and then they drop. It’s very fast growing until it hits about 90 feet, and then it gets wide, but I’ve got one that’s 25 years old and it’s about 90 feet tall.
Margaret: Wow, I have one, two… I have two of the plain green one, old, and three of the… Is it ‘Gold Rush’ or what’s the name of the cultivar of the gold-leaved one? Metasequoia, I think it might be ‘Gold Rush,’ but anyway, I’ll look it up.
Ken: It’s funny because it has another name, which is ‘Aurea.’
Margaret: It may just be that and ‘Aurea’ meaning yellow—or gold.
Ken: Gold, yes.
Margaret: Yeah. And the thing that I love about this majestic… As you said, it gets very big and it gets muscular big down at the base eventually-
Margaret: …and has shaggy, cinnamon-y bark. It’s really rooted, it looks like it’s so anchored at the base. But it has these very delicate needles, they’re just fine-textured and beautiful. And then sometimes around late winter, like if I’m doing spring cleanup or whatever, I’ll see on the ground these tiny little cones [above], like a size of a marble—beautiful cones. And this massive tree has these tiny little cones and it’s just so the juxtaposition just delights me each time I come upon one. [Laughter.] Yeah, so that’s a treasure.
Ken: That’s a treasure. And it was found in about 1948 in China, and it was thought to be extinct. They only knew it from fossil records, and some fossil records from the United States. But the living tree was found in China, then seed was brought over and grown at the Arnold Arboretum. And in 1950, some people got them, and it turns out it’s not so hard from seed [laughter]. So now a lot of people have them.
Margaret: O.K., so moving onward.
Ken: You want me to keep going? Listen, I could go. So this is a plant I want you to try to grow. And it is a Southern magnolia, which we think is not hardy, but there are a few hardy ones, but I have been growing it over 20 years: Magnolia grandiflora ‘Edith Bogue’.
And it’s not the prettiest Southern magnolia, but I have it growing on the road. And every winter it gets splashed with salt and it is a broadleaf evergreen, and it does have fragrant flowers, but this thing—wow, it’s tough as nails. And it’s gone down to minus-15 here once and it didn’t get burned or anything.
Margaret: And the leaves now they’re thick-textured, large, beautiful, shiny on one side, and indumentum, like a velvety covering, on the other?
Ken: Well, ‘Edith Bogue’ is a little light in the brown department. [Laughter.]
Margaret: O.K., but a lot of the Southern magnolia has had that indumentum the soft, fuzzy, felty stuff on the underside. O.K., so do those leaves then dry up and fall off every few years? Or-
Ken: Yeah, it’s sort of… Well, I can’t even say its semi-evergreen, because it’s never without leaves. It’s kind of like what we call an evergreen azalea—it tends to drop about a third to half of its leaves. And if you put it in a place where you don’t care, then it’s not a big mess, but it happens all at once. So you can just rake them up if you care. As I said I have it against the outer edge of the property, along the road as a screen, and it’s wonderful because it does get tall, and I just let the leaves drop where they do.
Margaret: And flowers?
Ken: The flowers are close to 12 inches across and they’re white and fleshy, and they don’t last very long. But ‘Edith Bogue’ the flowers smell very lemony. I have another one called ‘Bracken’s Brown Beauty’ that isn’t quite as hardy and it’s dwarf, lots of brown felt and its flowers smell like ginger.
Margaret: And you’re Mr. Scent over there. You did that-
Ken: I sure am.
Margaret: …“The Scentual Garden” book this last year about scent in plants. So you would know; you would have gone around sticking your nose in all of them comparing.
Ken: [Laughter.] I do that, I stick my nose in everything.
Margaret: My oldest… No, that’s not true; that’s a lie. The oldest tree that I bought when I came here, as opposed to brought with me from my former garden in Long Island, in Queens, the oldest tree is the Magnolia. It’s a deciduous magnolia. It’s a Loebner hybrid; it’s Magnolia x loebneri ‘Ballerina.’
And the thing… A nurseryman nearby, at Windy Hill Farm in Great Barrington, Massachusetts, a great nurseryman, Dennis Mareb… He said to me that first year—I didn’t know him or anything—and I went there and asked, “What should I have as a magnolia?” And he said, “You want these because these bloom 10 days later than others, and therefore you’ll never lose your flowers to a late frost.” He said, “It’s just those 10 days that make a difference.”
And I don’t know if that’s the exact formula, but that was his observation, and he’s planted them—he does landscaping as well—for the last 40 years, and has planted them for many people. And don’t you know, in all these years, I’ve always had flowering on that magnolia. Because a lot of them you can get those nasty brown… And sometimes I’ll get on the last bit of the flower flush, I’ll get a few that will go brown in a late for us. But I’ve always had flowering, so that’s nice.
Ken: I finally removed my soulangeana, the very common, I don’t know what…
Ken: Yeah, it’s pinky-purple.
Margaret: Saucer magnolia.
Ken: Right, and it was old but I think the blooms hung on, one out of every five years, it’s just, it’s not worth it.
Margaret: So, I’m going to throw in a couple of trees. I said just now that was the first one I bought after and I brought one along and it’s definitely my treasure of all treasures. It’s a conifer, it’s the Sciadopitys verticillata, the Japanese umbrella pine. It’s not a pine at all, it’s very ancient. It’s like Gingko, it’s the only one in its genus, it’s monotypic—is that what you call that when you’re the only one in your genus? [Laughter.] [Above, the upper two-thirds of the umbrella pine straight against a winter sky.]
Ken: Are you accusing me?
Margaret: I’m the only one in my loony world and it’s the thing that everybody loves when they come for garden tours, in years we can have garden tours. And I brought it… I had started a garden at my mother’s house when she was ill, when I was in my 20s, my first gardening experiences and I had planted this then very, very rare conifer. And I just couldn’t bear to leave it with me when we had to sell the house, eventually, when she was too ill. And I brought it with me in the moving van, in a bushel basket and planted it and it survived. I didn’t know anything about hardiness zones then. And every day I think “We came here together that tree and I,” so it’s a highly loved tree.
Ken: That’s another tree that in the old days, they didn’t know how hardy it was or they would say, “Oh no, you can’t grow this,” but you can.
Margaret: So that’s a favorite for sure. You want to tell me another of yours?
Ken: Sure, well, I was thinking about telling you about my Cornus florida ‘Urbiniana,’ which I have grown from seed. I’m not going to get into it too much, but now in its eighth year, it has flower buds all over it, and it has… It’s a dogwood, a white-flowering Cornus florida from the mountains of Mexico. It’s perfectly hardy, and the flower brachts are fused [above, at Ken’s]. So they look like little flying saucers.
And I’m going to have my first flowers on about five of these trees. And if they’re not fused, those trees they’re going away [laughter]. I’m going to cut them down because they’re in the way and they’re very tall. But that’s just something that’s on my mind because they haven’t ever bloomed before, and growing trees from seeds, hmmm. They’re easily 15 feet tall.
Margaret: All right, so this is another getting back to that sort of, why are so many trees grafted? Because when you use an asexual or clonal form of reproduction like grafting, you end up with the exact thing that was in the previous generation. And so by starting these from seed—and I have from the same nurserymen that I just mentioned, I have a Cornus kousa from seed. So when I bought it from him, there were named ones that I would have known exactly from the pictures in a catalog what the flowers would have looked like and blah, blah, blah.
But this was much cheaper, and it was fun, and I thought, “Hey, Dennis grew these from seed, I’m going to buy one,” because I loved his other things over the years. But I didn’t know in advance would have big flowers, lots of flowers, small flowers… Do you know what I mean?
Margaret: So, because genetics vary in a seeding population, there’s the great variation in the genetic and the gene pool, which is how plants survive, and adapt, and thrive, and go on for zillions of years is by having-
Ken: Did you say, whether you’ve got flowers on that?
Margaret: I did. There was no way to see the flowers; I bought it very young.
Margaret: But once it started flowering, it was fabulous.
Ken: I have a couple of Acer japonicum ‘Acontifolium.’ Because it has leaves like an Aconitum, which are very divided—one of my favorite plants, and I’ve grown them from seed. And one of them is about 35 years old and really has the best fall color of anything. But I can’t actually say that it’s an ‘Acontifolium’ because it’s from seed, even though it really resembles the selection completely, it looks just like it. [One of Ken’s seedlings in fall color, above.]
Margaret: So what you just said in Latin gibberish, is that it’s the Acer japonicum, or Japanese maple, and acontifolium, which means it looks like an aconite or a monkshood, which is a herbaceous perennial. How’s that for a mouthful? [Laughter.]
Ken: Oh, I love it.
Margaret: I have a lot of Japanese maples, which I grow in pots—very, very large pots—and take into the garage, the unheated garage, to store them for the winter. And that’s a whole other story, which we’ll talk about another time.
But I used to grow… And I’ve had two losses in recent years of favorite trees, longtime friends that were with me: Acer pseudosieboldianum, which is a Korean maple sort of looks like a Japanese maple, but hardier and the same nurserymen, again said to me, “Margaret, if you want a ‘Japanese’ maple, quote unquote, to go in the ground here in our cold Zone 5B and do well year after year, it’s either the ‘Bloodgood,’”—the typical reddish one you see, or, and this is back a lot of years, “or pseudosieboldianum,” this Korean one.
It was just fabulous for years and years and years, decades. And then one day it just literally, it never leafed out, it wasn’t even sick the year before. And I assume was some fungal disease or something underground going on, that succumbed to a disease that was hidden. So very, very sad, I didn’t want to replace it because if there was a disease in the soil, etc. But that’s a fantastic, incredible fall color, like nothing you’ve ever seen and hardy as a bone, so pseudosieboldianum. Yeah, so a couple more?
Ken: Did you ever grow a paperbark maple?
Margaret: I haven’t, but I liked them and I see them around here. Yes.
Ken: Acer griseum. It has exfoliating bark, which is sort of amber, and there’s a lot of it in the fall, the sunlight just illuminates them, and it looks like all these shaggy bits are glowing. That’s a beautiful and very popular, slow-growing, smallish maple, beautiful. Grown for its bark.
Do you talked about diseases and stuff, maybe we shouldn’t get into it, we won’t. Do you know Abies koreana ‘Horstmann’s Silberlocke’?
Margaret: I don’t know that Korean fir, but I just have plain old Abies koreana—and purple cones, incredible cones [above, at Margaret’s].
Ken: Incredible cones. Well, on ‘Silberlocke,’ the needles curve [below, at Ken’s]. So if you ever look at the bottom of the needles on your fir there’s silver on the bottom they’re glaucous. Well on ‘Silberlocke’ they curl around, so that silver is all around the whole branch and can be seen from the top. That ‘Silberlocke’ means silver hair, so it’s really amazing.
Margaret: So we mentioned kousa dogwoods, but we didn’t mention any other dogwoods. Do you want to quickly-
Ken: I mentioned the ‘Urbiniana.’
Margaret: Oh, you did, that’s right. Do you grow any of the other ones?
Ken: Well, I didn’t get into the kousa ‘Wolf Eyes,’ which I’ve had something wrong with it.
Margaret: Mine died.
Ken: And after years and years, a beautiful variegated kousa dogwood with nice flowers and everything, white flowers, and it was a showpiece, it stopped traffic, this gorgeous tree and all of a sudden it started to decline, I’ve had to cut some parts out of it. I think just like you said, it’s some kind of wilt disease that’s in the soil or at the bottom of the trunk, and it’s sort of killing off that cambium layer beneath the bark, you can’t really see it. And I don’t think you can treat it, either.
Margaret: The only thing there and my nurserymen friend also said to me, when I lost my Korean maple, he told me the name of the pathology lab, the nearest university one, at UMass-Amherst. And he said, “You could send your samples there.”
The extension systems throughout the country can tell people if they really want to know, because sometimes you want to know if you can replant with a similar species. You can get a diagnosis if you really want to send in material for a test and they tell you what to do.
So I wanted to say one that I lost, another one that I lost… I’m just talking about dead trees [laughter]. But seriously, and this is a great small tree… I’m crazy about the Aesculus I guess they’re buckeyes, is that right?
Margaret: And lots of different shrubby ones. And there’s a small tree with red flowers called Aesculus pavia, the red buckeye [above, at Margaret’s]. And I had that for so many years, and then similar to that maple, last year It just didn’t leaf out. It didn’t decline, it was beautiful the year before, and then boom! So, go figure, but that’s one that I will replace. I’m going to put it in a different spot, but that’s one that I don’t want to garden without it so-
Ken: Have you taken out the body?
Margaret: Yes, I did.
Ken: So it had roots and everything-
Ken: So it wasn’t like something ate the roots.
Ken: If anybody goes to Williamsburg in Virginia, there are some there that are very old, probably almost 50 years old, if you can imagine, and they are thick trees, they’re not tall like you said. But in bright sun in Virginia, they’re just magnificent, incredible trees. For us they’re very small trees. [Laughter.]
Margaret: So you have exactly a half a minute to tell us about one more. Do you have one more on your-
Ken: Cercidiphyllum japonicum ‘Morioka Weeping,’ which is a weeping katsura [photo, top of page]. And that’s… well, katsura is the common name. And this one, ‘Morioka Weeping,’ is tall, it goes up to probably to about 30 feet, and then it’s just dripping with these long, weeping light branches. But there’s another one called ‘Pendula’ that only goes to about 10 feet. It’s 10 feet tall and about 12 feet wide. And I have them both, and I also have the species, and it has great fall color. And there’s my 20-second tree.
Margaret: He’s a tree addict folks; he’s just confessed it. And we didn’t even mention crabapples, which is the tree I have the most of. Anyway, another show Ken Druse; thank you very much. And ho, ho, ho, and I will talk to you soon.
Ken: My pleasure.
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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 11th year in March 2020. In 2016, the show won three silver medals for excellence from the Garden Writers Association. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the December 28, 2020 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify or Stitcher (and browse my archive of podcasts here).