A FEW OF THE GARDENERS I’ve learned the most from over my career have one thing in common: They’ve worked at Wave Hill, the exceptional public garden in New York City, perched above the Hudson River with world-class views and much more.

Even though my own garden is put to bed, the wheels in my gardener brain are still whirring. I’m looking for the seeds of ideas for the year to come, so to that end lately I’ve been rereading a book published just a few months ago, “Nature into Art: The Gardens of Wave Hill,” (Amazon affiliate link) and from it and its current Director of Horticulture, I got some practical inspiration. Louis Bauer is just the third director of horticulture in Wave Hill‘s history, though the garden in the Riverdale section of the Bronx was founded in 1965.

He shared tips on upcycling prunings into plant supports; how easy hedges can create serious architecture; how to encourage desirable self-sowns like poppies, larkspur and others to flourish; how repeating shapes (not just colors) can strengthen your designs; and why we each need one blank bed to “play” or experiment in each year.

Read along as you listen to the December 16, 2019 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Spotify or Stitcher (and browse my archive of podcasts here).

Plus: Enter to win a copy of the book in the comments box at the very bottom of the page.

wave hill garden wisdoms, with louis bauer

Margaret Roach: Happy winter. Oh, my goodness.

Louis Bauer: It came with a vengeance.

Margaret: It did. When the book came out, I just want to remind people, I did an interview with its author, the garden writer Tom Christopher, who’s a friend of both of ours. And we talked about some of the sorts of lessons of Wave Hill’s style of gardening. I’d like to dig a little deeper into some of those with you, and also some additional thoughts I’ve picked up on in my second read of the book, of “Nature into Art.”

So maybe first of all most practically: You guys are really frugal. [Laughter.] I mean, it’s not like you have a bazillion, trillion, quadrillion-dollar budget to just go out and do whatever you want, so maybe that’s why. But you collect and age leaves to make mulch; you compost, of course. You grow a lot of things from seed, which takes a long time, but it’s easy on the budget. Is your motivation purely ecological or budgetary or what?

Louis: Well, maybe I should start by saying it’s partly history, because in 1965 the garden really did have a tiny budget, and for a few years after Marco became the first Director of Horticulture at Wave Hill-

Margaret: And that’s Marco Polo Stufano, the original Director of Horticulture.

Louis: Yes. He had a really tiny budget, and I think it was partly by his nature. I think that it shows in the character of the garden. There are some kinds of being frugal that really lend character to the garden, and forces you to grow things from seed and really know the plants from the seedling up to a mature plant. Or collecting your own pea sticks for staking and, as you said, your own mulch and compost.

You really know what’s in it. You know how to use it; you know what it’s going to do. You’re not going to the local box store and what they offer all of a sudden changes—it’s something completely different. It has a lot of advantages.

Margaret: Mm-hmm. So it’s not just sustainability, so to speak, or budgetary, but it’s organic in the sense of everything is of the place and of a piece.

Louis: Right. Of course, we don’t mind saying these days that it’s also ecologic and sustainable.

Margaret: Yes.

Louis: But they’re kind of catch phrases that we’ve always done without having the catch phrase.

composting: chop it up first!

Margaret: [Laughter.] O.K. So one of those things is composting. You must have, I mean, I only have a 2-acre garden or whatever, a little over 2 acres, and my compost heap is this massive open pile. It’s, I don’t know, 40 feet long and 8 feet wide and very tall at the peak times of year when there’s lots of fresh material. I mean, yours must just be a football field. I don’t even know. But how in the world?

Louis: Well, close to that.

Margaret: Yes. So what is your method, and are any insights or anything you can share about that? Because I think that’s something that people are always … Do you compost hot; do you turn it a lot? You know what I mean.

Louis: We don’t compost it hot and-

Margaret: Yes, me neither.

Louis: And from the beginning it was an open pile, like yours, and we weren’t particularly careful about it. We happened to have some rough terrain that’s not really accessible to the public, with a generous amount of space to have a big pile. So we had the luxury of just waiting for it to take a long time to break down.

But space keeps shrinking. Even though our property is the same size, we develop more of the garden. The garden sort of creeps out and gets a little bigger and our compost is getting squeezed. So we are just… the new Assistant Director is giving it a little more attention, and we’ve expanded what we collect. It’s not just the garden clippings and the leaves and the chipped wood that we prune.

Now the rest of our staff… Wave Hill is more than just a garden; we have an arts program and education, and those departments want us to incorporate their kitchen waste.

So we started doing that and using a tumbler, because we didn’t want too much food waste in our pile, in the city.

And that’s really kind of again focused us on, well, are we really being as efficient as we could be? Could we make our compost pile a little neater? Maybe people even want to see it. We don’t have to take them to a football-size place, if we do a little more chopping and a little bit more turning and pay just a little more attention to how we put it in the pile.

Margaret: Yes, yes.

Louis: In other words, mixing the green and the brown.

Margaret: Yes. And the way you just said chopping. The smaller we make the debris before we put it in. I mean, even just cutting it up a little bit really helps, let alone shredding or something like that. But it really, really helps to speed, obviously, the decomposition. Yes, that can speed it up.

Louis: It makes a big difference.

Margaret: Yes, it makes a big difference. I’ve wondered about the tumblers. I’ve never tried one, so interesting that you’re using it with the food scraps.

Louis: Yes. We still don’t use any meat or-

Margaret: No, of course.

Louis: … protein or any of those things in it. It’s not a closed system that could accept that. But because they’re cooked vegetables that might attract vermin in the garden, we have been putting it in a tumbler and it doesn’t take any extra space. Just a few extra minutes every week to collect and give it a few turns. And it’s great.

turn prunings into plant supports

Margaret: Yes. So one of the things that you do, and Tom Christopher, the author of the book, and I talked about this briefly and I wanted to know more about it, is that when you’re pruning, you keep certain things in order to use them later as like stakes and other support mechanisms. I wondered if you could give me an example, because it made me feel like, oh, my goodness, I’ve been squandering my brush pile all these years. [Laughter.]

Louis: Well, there are a few things that we don’t put in the brush pile and instead make into some bundles that we stuff into a corner of the garage. Or I guess if I were doing it at home, they’d go into the corner of the tool shed. Those are some tough perennials, which most people don’t think of saving if you do grow them.

Lespedeza and Baptisia have such stiff, durable stems that they make great supports for young things in the spring, like sweet peas and Clematis just coming out of the ground. We use them in the greenhouse occasionally, too, for the winter climbing vines that we display in the Palm House.

Margaret: Oh, so when you don’t need a big heavy trellis-y type of, or big stake, you use even some herbaceous things that are sturdy but not woody. Not big, big thick woody.

Louis: Right.

Margaret: Yes. Oh, interesting. Lespedeza, Baptisia. O.K.

Louis: They’re very fibrous and they’re fairly straight, so you can make them into a tidy bundle if you have to store them for the winter. And use them in the early spring for things that are tender and just coming up.

In the winter or toward the end of winter if we’re doing pruning on spireas or birches or some of the willows—not the bigger-growing willows, but the little willows like [Salix] purpurea ‘Nana,’ which we use as a hedge. They make very fine-textured woody stems, almost like the Lespedeza, but a little bit stronger and tidy. They have short internodes and they’re very branchy, so they make good support for low perennials. [Above photo: Trimmings from Salix alba var. vitellina woven into place as a support for emerging sweet pea seedlings.]

Margaret: O.K, so low perennials. So it’s the springtime. Everything’s coming up out of the ground, all my perennials. I’ve cleaned up, and when do I put this… What did they used to call it, brushing up? Some of the brushing up.

Louis: Brushing up. That’s right.

Margaret: As opposed to staking for a more formal staking. So give us some examples of some plants and perennials that people might know that might benefit from this. And you kind of put it around the perimeter of the clump or what’s the idea?

Louis: Usually around the perimeter, but sometimes in the center. One of my favorites is shrubby Clematis.

Margaret: Right.

Louis: And maybe that’s a little bit esoteric.

Margaret: No, no. No.

Louis: But there are some strictly shrubby Clematis and some that are just very low growing, sort of sprawling. It doesn’t really climb. And these kinds of stakes are great for that. They’re not strong enough for things like peonies, which generally you need a sturdier stake for.

Margaret: Right.

Louis: But I don’t know. If you’re growing … Hmm. [Laughter.]

Margaret: Well, that’s a good example. So something that would otherwise get kind of floppy, you put this in when it’s emerging and it provides like an armature for it to… a little extra help.

Louis: I’ll use some stiffer things too, like willows and the colored twig Cornus, because they’re flexible and perfectly straight. And you can make arches or a straight grid or a more traditional-shaped trellis out of your own twigs.

Margaret: What if you made like a grid the way a peony ring sometimes that then people might have seen in the garden center, has like a grid of metal on the top? If you made a grid for something, what would you lash it together with? Would you use twine or something? Or it would just be …

Louis: Jute twine is usually our first choice.

Margaret: Jute twine. All right.

Louis:  But sometimes we get a little fancy and we have some finer-textured hemp twine, which is just a little more discreet if you want something that’s going to show and you don’t want to see all the twine and the knots.

Margaret: Right. So we’re going to get crafty. I better get crafty. I’ve got to re-cultivate my Martha Stewart DNA that I used to have. [Laughter.]

Louis: Exactly. And the jute twine is easy to find at the craft stores, so you’re right on track.

encouraging, and editing, self-sowns

Margaret: Yes, yes. So I said in the beginning that you grow a lot of things from seed and you also do something frugal, which is… I call it shopping in your own garden. Which is sort of finding self-sowns and using them. But the thing that’s frustrating about self-sowns is, and a lot of biennials and certain annuals do this, they might give you a lot of babies, but last year’s plants don’t always plant their babies where they paint pretty garden pictures. Right? Like they’re a hundred in the cracks.

Louis: Right. They kind of come in … Exactly. There are a few things that seem to only want to grow in the paving cracks and that’s not very practical.

Margaret: Yes.

Louis: Or right at the edge of the bed.

Margaret: Yes. One of your big ways that you garden there is that you do utilize these things but you edit, don’t you?

Louis: We do. And to help defeat the problem of them only seeding into the paving cracks, some of them, in the fall we do a little extra cleanup so that there is clear ground and they fall in the middle of the bed and come up not just at the very edge. Because some of these need a little space and light. And if you’re careful to do that, they’ll come up in the middle of the bed where you want them.

Margaret: Oh. So you anticipate the self-sowers and give them a little extra open soil around where those seedheads are. Oh, oh.

Louis: And you don’t load it up with mulch at the end of the season.

Margaret: Right.

Louis: You kind of leave some bare ground for them.

Margaret: Oh, boy. What have I been thinking all these decades? [Laughter.]

Louis: Well, mulch is great, but it doesn’t marry very well with things like larkspur and foxglove and poppies. They need a little bit of open space. So you can watch all the places where they’re not growing, but if you’re cultivating them, you need a little bit of open ground.

Margaret: Right.

Louis: That makes them easy. And then you may not have to move them. You really do just edit out the extra ones.

Margaret: Thin them out a little bit. Yes.

Louis: Right.

Margaret: Yes. I find a number of biennials, like angelica for instance, some of the biennials I find do sow around a lot. Things like calendula, sow a lot—an annual. They sow like crazy amounts if you ever have them.

Louis: Well, there’s sort of a wide spectrum of the ones that sow just a few and you have to guard them and maybe move the few. And then there are the ones that just make thousands and the only job is editing them out. So for us, the ones that are so prolific are things like Perilla and Atriplex and Nigella.

Margaret: Yes.

Louis: And there’s a new pink-flowered Queen Anne’s lace.

Margaret: Oh, yes. It’s not Ammi majus, is it? Is it Ammi? No, that’s-

Louis: No. It’s Daucus carota ‘Dara.’ [Above photo by Ken Druse.]

Margaret: Oh, Daucus carota. Right, right, ‘Dara’, right. I don’t know why I can’t remember that. Yes.

Louis: Well, the first year or two we grew it, it made just a few seedlings, but by the third year they were everywhere. So it’s in that group of things that makes lots of seedlings, and so you have to be careful to edit a lot of them out.

Margaret: Nicotiana, I’ve got the national collection over here of Nicotiana, in the spring, millions of seedlings. And Verbena bonariensis also; I find that I get a good number of those. Those are some other things.

Louis: Those kinds of plants are interesting because people get a little disappointed, because sometimes the first year or two they don’t really seed in very much. You have to be a little persistent at coaching them the first couple of years. But as you said, pretty soon they’re every everywhere that you could possibly want them.

Margaret: Well, and another thing, Louis, that you just made me think of is that in those first couple of years, the gardener has to get aware of what the seedling looks like of this new friend that they wish to cultivate. Because sometimes not only by maybe mulching around them and not giving them a hospitable place to sow successfully, like you were just saying, but also sometimes you don’t know what they look like and they don’t look like much at first. And then you go out in spring cleanup and you tromp on them, right? I mean, that’s another thing.

Louis:  Right. And Nicotiana has the bright green little round leaves. And larkspur has little fine hair-like leaves. So you do get to recognize them and you look forward to seeing them, I think. I do.

Margaret: Yes. And I think that’s really true for, we need to know our weeds and we need to know our seedlings, both the undesirable and the desirable at very small phases—like what they look like when they’re tiny. I think that’s helpful.

Louis: So that’s another reason that growing plants from seed is kind of useful, because we grow them not only self-sowing like that, but we also sow them in our greenhouse and in our cold frame. And so we get to see them in a pot. Maybe that’s educational, too. Sow a few in a pot so you know what it looks like when they come up, and you can watch for them in the garden by learning that way.

repeat not just colors, but shapes

Margaret: Right, right. In the chat I had with Tom Christopher about the book, we talked about one design principle that you observe or has traditionally been observed at Wave Hill, which is you have this incredible view across the Palisades, across the Hudson River and that you kind of echo on your side in the garden. You echo some of the color palette of what may be seen seasonally across the way.

But I think you use other sort of echo techniques in design there, too, to sort of shift to talk about design for a couple minutes here.

Louis: Well, it’s not quite as obvious. And I have to admit, I didn’t think about it very much until I saw the pictures in the book. Ngoc Minh Ngo takes such wonderful pictures that it made me see things in a new way. I realized that a lot of my favorite spots in the garden are places where in the foreground there was a perennial or a small shrub, and in the middle ground there may be a tree or a big shrub. And then in the background there’s something in the distant view and they kind of repeat or complement one another. [Above, mound-shaped perennials and shrubs in the Flower Garden seem to echo the Japanese maple and large trees beyond.]

So when I heard, well, obviously you know—Tom wrote about how the colors do that in the landscape, how the things we plant in the foreground kind of pick up on the fall color in the Palisades or the trees across the way. But the shapes do that, too. I noticed it in Ngoc’s pictures.

Margaret: So you would have a shape, whether it was a big, round-headed thing and there might be a round, blobby kind of shrub more in the foreground and it’d be round-headed tree further on. Is that what you mean? The kind of repeating shape?

Louis: I do. There’s a picture Ngoc took with some Stachys byzantina, the silver, spiky, early summer flower, and in the middle ground are pale blue tuteurs and agaves, and in the background is a multi-stemmed gingko with all these pointed tops. It’s subtle and it’s not something that you can always plan for. I think some of us do it intuitively.

But I think even in a small garden, if you take pictures—or I’ve even heard a couple of gardening friends say they take black and white pictures to see these kinds of things and they tell me something new.

Margaret: Because they don’t want to be distracted by the color. Is that what you mean?

Louis: Right. They want to focus on another aspect, and it really makes the garden feel whole when the shapes fit together and not just the colors.

Margaret: So they do black and white pictures and they kind of erase the color distraction. And then they look at the units, the shapes, and they think about whether they can …

Louis: The shape composition.

Margaret: Yes. Oh, interesting. That’s a good exercise for all of us to be doing at each different season, really then isn’t it?

Louis: Well, some of Ngoc’s most breathtaking pictures I think are in the early winter,  when the grasses are tan. It’s not covered with snow yet, but all of a sudden you see shapes and there’s a little mist that cuts out some aspects of the garden. And those tree silhouettes and shapes of grass mounds and shrubs really show.

Margaret: Huh. Just quickly, do you use any of the, speaking of grasses, they’re almost like woody stems, a lot of the bigger Miscanthus and stuff. Do you use any of them? Do you save any of them for your brushing up or anything?

Louis: Yes, we do have some bamboos and Arundo donax, which make pretty sturdy stems. But the truth is that most of them in our climate don’t get hard enough to last very long. They’re kind of temporary.

Margaret: O.K. All right.

Louis: But we have for some occasions used them.

Margaret: Yes, I was just curious.

Louis: I would say one more thing about them, though. If we go the way back to the compost, those are some of the things that are most advantage in chopping up. We don’t think about grass being woody.

Margaret: Oh, but it is.

Louis: But it takes a long time to break down if you don’t chop it up,

Margaret: It really is. The ornamental grasses really need to be pre-shredded or chopped up. Yes, yes.

architecture from easy hedges

Margaret: So, O.K. I want to just really quickly talk about hedges, because I saw this picture in the book—speaking of pictures in the book—a picture, there’s a path and on one side is a hedge and on the other side is the hedge, but one is a deciduous hedge and one is an evergreen hedge and they’re flanking this path [above]. Speaking of structure, again too, right?

Louis: Right. Those were planted by Marco just before he retired in about 2000 at our Aquatic Garden, which is the most architectural, I think, space in the gardens. They’re not that old, but in the picture they make the garden look like an ancient, majestic kind of place. Because …

Margaret: Yes. Really creates architecture. And so one is, what? European hornbeam, I think, Carpinus? Is that what it is?

Louis: It is. It’s European hornbeam, Carpinus betulus, and on the other side is Thuja plicata.

Margaret: So the Western red cedar. And they get pruned once a year or a lot of times?

Louis: The Carpinus gets pruned twice a year and the Thuja gets pruned about every three years.

Margaret: Oh, oh.

Louis: It keeps its shape a long time.

Margaret: O.K. Oh, interesting. Oh, so those are two really good choices for people who are looking to create some structure or an enclosure. Those were two really amazing choices, I thought. We’ll show a picture with the transcript as well, but yes.

leaving a blank bed to ‘play’ and experiment in

Margaret: Again, when I spoke to Tom and we mentioned the Paisley Bed [above], which is this bed near the greenhouse, the conservatory, that is different every year. It’s kind of an empty, a tabula rasa, blank canvas.

Louis: Twice a year it’s different.

Margaret: And it made me … Oh, it’s twice a year it’s different. It made me so jealous, because I don’t have an empty bed. And I really feel like everybody ought to and I ought to. So tell us a little bit about that spot.

Louis: Well, I think at first glance people think it’s a little leftover Victorian-era planting bed. But it’s not very big, so it’s not a huge burden. It’s a narrow, curved bed, about 35 feet long and about 4 or 5 feet wide at the narrow end and it’s-

Margaret: A paisley. [Laughter.]

Louis: Yes. A paisley. In the spring we fill it with cool season violas and pansies and calendula and tulips. A little bit different color scheme every year. And about Memorial Day, we change it over to tropical plants, and that’s when we get a little bit wild. We try make it as different every year as possible. Marco did a number of wonderful schemes that were purely about color, all purple and orange or all turquoise and pink.

Or one year we had a construction project and we were left with all of this sort of iridescent copper flashing, so it had sort of some impromptu sculpture mixed with bronze and purple and red. Mostly foliage, but a few flowers. We’ve done some formal vegetable gardens in it.

Margaret: So the possibilities are limitless, really. It’s a place to play and experiment.

Louis: It is. I even did a couple of schemes recently that had all plants from a particular region of the world, all West African.

Margaret: Fun. [Laughter.] Well, Louis Bauer. I love the new book. As I said, I was just rereading it. I’m on my second time through “Nature into Art: The Gardens of Wave Hill.” We’ll have a giveaway with the transcript of the show and lots of pictures of what we’ve been talking about. I appreciate your taking the time. Thank you so much.

Louis: You’re very welcome. My pleasure.

more wave hill garden-making lessons

• My interview with “Nature Into Art” author Tom Christopher about other gardening lessons from Wave Hill

(Photos except of Louis Bauer and of Daucus carota by Ngoc Minh Ngo, for “Nature Into Art: The Gardens of Wave Hill.”)

enter to win ‘nature into art: the gardens of wave hill’

I’LL BUY A COPY OF “Nature Into Art: The Gardens of Wave Hill,” for one lucky reader. All you have to do to enter is answer this question in the comments box at the very bottom of the page:

Did any of these tips strike a particular chord with you? (As I said, I’m craving the “blank bed” to experiment in–and need to look more closely at my prunings for helpful, artful supports-to-be…plus the idea of photographing in black and white to better see the shapes is genius.)

No answer, or feeling shy? Just say something like “count me in” and I will, but a reply is even better. I’ll select a random winner after entries close at midnight Tuesday, December 31, 2019. Good luck to all.

(Disclosure: As an Amazon Associate I earn from qualifying purchases.)

prefer the podcast version of the show?

MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 10th year in March 2019. 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 16, 2019 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).