dividing and editing perennials, with wethersfield’s toshi yano

MAYBE YOU, like I do, have certain perennial beds that could use editing and some particular plants that need dividing in the process. That’s just one focus of today’s guest, Toshi Yano, in his role as director of horticulture at Wethersfield, a former private estate turned public garden in the Hudson Valley of New York. He’ll tell us the how-to, and also about visiting this special place.

Toshi is in his third year as director of horticulture at the former estate called Wethersfield garden in Dutchess County, New York, with its 3-acre formal gardens plus 7 acres of wilderness garden and commanding views of the Catskills and Berkshire Mountains.

Toshi and his team are bringing the gardens back to life, and he told me about the place, and specifically about the tasks of editing and dividing that every perennial gardener needs to do, whatever their garden scale. (Above, a tangle in one of the Wethersfleid cutting garden’s annual beds, with Gladiolus ‘Wine and Roses,’ Zinnia ‘Benary’s Giant Lime,’ Rudbeckia hirta ‘Indian Summer,’ Lathyrus odoratus ‘Judith Wilkinson’ and Tithonia rotundifolia all clambering for space.)

Read along as you listen to the Aug. 23, 2021 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).

editing and dividing perennials, with toshi yano



Margaret: Hi, Toshi. Busy, busy, busy.

Toshi: Well, we finally have some sun. It’s been such a rainy, wet, cool year.

Margaret: So can we start with just a quick little intro to Wethersfield? It’s wethersfield.org, not like the weather, dot org—the website. And just a little about what is this place?

Toshi: Sure. So Wethersfield is the former estate of a man named Chauncey Stillman. He was a gentleman farmer, a student of architecture, and a patron of classical arts. Wethersfield was sort of his experimental laboratory, where he got to introduce lots of new farming techniques. He started the estate after the Dust Bowl, and brought over a Kansan farmer, and they introduced a lot of new soil and water-management techniques. And at the same time, he created a very unique garden.

He was sort of the last entry to the country place era gardens. You know, post-income tax and minimum wage, a lot of these great estate gardens sort of fell by the wayside.

Mr. Stillman was the grandson of the person who had founded Citibank, so finances weren’t really an issue for him. And he created this very intricate, formal garden at the top of a hill, and he and his friends, who were all classical scholars, really went to extremes to recreate an Italian Renaissance garden full of formal hedging, topiary and in addition, a woodland Bosco garden full of statuary telling an allegory of a descent into the afterlife, and in a sense out of it into paradise, basically.

Margaret: [Laughter.] Oh, boy. [Above: A view of the Taconic Range over clipped yew and the hot pink blooms of Rhododendron yedoense var. poukhanense.]

Toshi: So it’s a very unique garden in a lot of ways that takes most of its cues from the Italian Renaissance in a way that no other garden I think in America does with as much fidelity.

Margaret: Right. So you arrived three seasons ago, approximately, at this place in the formal Italian tradition. And it’s big and it’s got all kinds of elements that need loving care and so forth, lots of beds and borders.

What’s the palette of plants like, especially in the borders? I understand there are pleached hedges and like you said, topiary, and all kinds of things in the woody world to give it structure, but what’s kind of the pallet or the signatures of some of these beds and borders that you discovered when you came?

Toshi: Right. So around the house, Mr. Stillman, when he had first bought the estate had designed an arts and crafts garden. So there are a number of garden rooms immediately adjacent to the house that sort of harken back to the days of Lutyens and Jekyll, and so they’re filled with flower beds. And when I got there, we had sort of spring plantings of irises and peonies, and then sort of late-summer plantings of flocks and monkshood and Japanese anemone. And that was sort of it. There was nothing midsummer, and of course we’re open from the beginning of June to the end of September. So all around the house and in our cutting-garden beds, we had an empty space where nothing was really blooming, and that was one of the first things that I wanted to address.

Margaret: Ah.

Toshi: We have a great archive with all the drawings and planting plans from about 1950 through somewhere in the 80s. And so I was able to go through and see what had been here and what had been lost, and work from the historical plantings, and adjust them a little bit to contemporize them. And that’s sort of where we are now, in the middle of addressing all those issues. [Above: The tempietto at  Wethersfield’s Belvedere in early spring, framed by obelisks designed by landscape architect Evelyn Poehler.]

Margaret: So big garden or small garden, my garden? [Laughter.] When will you be here Toshi to help this? Oh my goodness.

Toshi: If I ever find another… My garden is doing well. It’s a meadow more or less, shade meadow. And so yeah, that’s about all I have time for outside of here.

Margaret: Exactly. So where to begin? That’s always the thing and to avoid paralysis of not doing anything. So plants grow and so the way when we planted a bed five years ago or 10 years ago or in my case, in some cases, 20 or 30 years ago. Or what you’ve inherited, a bit of mixed perennials or perennials and shrubs—what it looked like at the time when it first grew in, it looks like dot dot dot, years down the road. Not the same, and the proportions have shifted and whatever.

So I assume that that’s when you want to apply that eye for editing and how do we get in the editing mindset? So people listening are not looking at the scale you’re looking at, but smaller, and so what do we do? We stand back, we take some notes, what do we do? [Below,: The cutting garden on the left, with Tithonia rotundifolia, Cynara cardunculus, Anemone x hybrida ‘Robustissima’ and more are fronted by a low clipped hedge of Salix purpurea ‘Nana’ and backed by arborvitae. Across the path, annual beds with pink Gomphrena ‘Fireworks.’]

Toshi: So for me here, I just watched the garden for about a year before I decided to make any kind of decision.

Where are the gaps in bloom time when we’re looking at beds and borders, how can we address those? What kind of plants can we bring in to sort of fill in those spaces? So the first year I started to edit, it was more about dividing the stuff that had been left to roam for decades. So mostly that was phlox and monkhood and anemone.

And so I did a lot of division and transplanting of those, so that instead of huge swaths of those plants, we had pockets. And I started to grow perennials to fill in those spaces, and then planted those out, and sort of waited till the next season to see how everything responded.

It’s a long process, especially in a garden this scale. But even at home, it’s not something we want to say, “Oh, I’ve done the division and that’s it, we’re done. I’ve transplanted.” We have to keep watching, of course, and making sure that things are moving according to whatever plan we have.

Margaret: And what you just said is first, looking for instance, for the gaps in the bloom time, and writing that down and keeping that front of mind is a really great guiding principle.

So besides their above-ground beauty, one of the other interesting things, fascinating things about all the plants we call perennials, they’re not just different above-ground, they’re different below-ground, too [laughter]. They don’t have all the same root structure, and I assume that, because you have a lot more expertise, you’re trained in this, etc., you know what you’re going to be up against.

But are there plants that you would or wouldn’t disturb in the spring or fall? Or that you just said for instance, the phlox, you decided, that it’s taken up too much territory. How do you then make a schedule based on what the plants are?

Toshi: So in a lot of cases, I do. I mentioned that we had irises and peonies for the spring, and those needed to be divided and moved, but they are not happy to be divided or moved in the spring.

We wait in the case of irises with their rhizomatous structure until July or August traditionally, to divide them and the peonies, we wait usually until fall, early fall, September, to divide those. And it’s because of, as you said, their underground structure. They require different division  than something like phlox, which can really be divided almost anytime.

Although, because of all the work we’re doing with annuals as well here and planting those out, I tend to wait until fall to do most of my divisions, and not do them in the spring.

So yeah, the root structure will tell you a lot about how to divide something, the more woody-rooted plants usually require like a garden knife, as opposed to the more fibrous-rooted plants, which require garden forks or hands.

So the plants tell us a lot, and if you’ve not done it before, it’s always good to get a sense of what you’re dealing with, either looking on the internet, which is always a helpful reference. Or my favorite place to go—and it was always recommended to me when I was in school, is this, you can find it almost anywhere in any used bookstore or on the internet—is the “Reader’s Digest Illustrated Guide to Gardening” [affiliate link], and I keep it at hand. It went through so many editions and was a bible for so many generations of gardeners.

And even at the New York Botanical Garden, which is where I did the horticulture portion of my degree, the old-school gardeners there who know more about gardening than I ever will, swear by it.

Margaret: That’s hilarious.

Toshi: So that’s a great reference. I think “Readers Digest,” they had T.H. Everett, who was the Director at the New York Botanical Garden, do his encyclopedia, a shortened version I believe, for “Reader’s Digest.” So they had great authors and great editors, and they always kept it up to date until they stopped publishing. And then another great book is “The Well-Tended Perennial Garden,” by Tracy DiSabato-Aust [affiliate link]. [Above: The cutting garden’s mixed border in midsummer: Asclepius tuberosa, Echinacea purpurea, Centaurea macrocephala, Verbascum nigrum, Agastache ‘Blue Fortune’, Tithonia rotundifolia and Gladiolus murielae poking through a riot contained by a low hedge of Salix purpurea ‘Nana’ in front and a taller hedge of arborvitae behind.]

Margaret: It is great, yes. And that’s more contemporary, yes. A little bit more.

Toshi: That is more contemporary, and has really plant-by-plant recommendations for maintenance, division, when to divide, how to divide. And so obviously I’m sure you get tons of questions, when to divide this, when to divide that. And the internet is kind of a murky place where if you go on, you’re looking for a specific recommendation, you get a 100 different recommendations, and you don’t know where to go. So those two books I recommend a lot.

Margaret: Oh, great. I was going to say in some of the old style books you see, I’m visualizing out of memory, you’ll see a picture, you said something about a garden fork. And you’ll see two garden forks, back to back, their prongs stuck into a big clump of something, like hostas. And then the idea of pulling the handles of those two forks apart, so that you’re prying the root mass to a part, you know what I mean? That sort of old-

Toshi: Yes. Well, that’s the diagram that I always think of [laughter] when I’m doing those divisions. That’s how I was taught to do the more fibrous-rooted stuff. Put those forks back to back, and then move them, wiggle them, more or less. Pry that rootball apart.

Margaret: Right. And when-

Toshi: Then you have two. Instead of one plant, you have two plants now.

Margaret: When all else fails, there’s the… I have a bread knife, an old large bread knife, serrated knife, heavy-duty serrated knife from a million years ago. And that’s in my garden basket, my too basket [laughter].

Toshi: Oh, God.

Margaret: There’s always that.

Toshi: Oh sure, yeah. Hands are great. One of the things that, so my girlfriend is a director of horticulture at a public garden called Locust Grove. And when she brings plants home to our home garden from the nursery, she’ll take a quart-size plant and turn it into four or five plants just using her hands, which is a great lesson she learned when she was an intern at Wave Hill, from the gardener there, Harnek Singh.

And so that’s a great home-garden technique is just dividing plants that you buy from the nursery in small containers and turning them into, three, four, five new plants. So they’re all kinds of different techniques, serrated bread knives, garden forks.

And of course the garden forks aren’t… I had mentioned we have so much Japanese anemone here, and that’s not a great tool for dividing Japanese anemone, which have those massive woody roots and resent transplanting. So when you have something like that, that’s when the garden knife or maybe the serrated bread knife comes out. I try to keep my cuts as clean as possible when I’m dealing with that stuff, because not only do they resent transplanting, but they resent root disturbance, so.

Margaret: I had a friend who wanted to divide years ago, a border of ornamental grasses and he used a chainsaw [laughter] to divide the root masses.

Toshi: [Laughter.] Yes. I’ve heard of people doing that successfully. So whatever it takes. And those grasses, those ornamental grasses, after four or five years they’ll often get that dead, hollow center. It’s a great sign that you need to divide. So yeah, and those roots are impossible to get through. So I’ve heard of people… Well chainsaw, so this the first time I’ve heard of chainsaw [laughter], but saws, handsaws, I’ve heard of people using.

Margaret: So what we’re trying to say to people is lift it out of the ground and look at it, and do a little homework. You named two vintage wonderful books, and there are other probably resources. Look at it. And if it has… The roots of hosta look very different from the roots of a daylily, which look very different from the roots of a Coreopsis, which look very different from the roots of, you know. [Above: A misty morning in the cutting Ggarden, with beds of mixed annuals on the left and a mixed herbaceous border on the right.]

Look at it, and in the way that… I know this is going to sound completely nuts, but it won’t be the first time I sounded completely nuts [laughter]. If you ever had a necklace in your jewelry jar or box or whatever, and it got tangled up, you have to look carefully to figure out how to untangle it. And it’s the same thing with roots of perennials. You’ve got to look, you’ve got to look. And sometimes I wash things, do you know what I mean? I wash them first when they’re out of the ground, and I really look.

Toshi: Sure.

Margaret: Which washing, I don’t know about you, but if there’s weeds in the bed then I’m doing, I always wash things before I move them to a new bed if there’s bad weeds in anything.

Toshi: It’s a great move, and I like to, if I have time. And sometimes it’s just a mad scramble to get as much done as possible. So it is a great idea, especially like you said, if you have weeds, but to get a really great look at those roots because the roots will tell you almost everything you need to know about how to divide the plant, as you’re saying.

Margaret: So we might then start with our analysis, look for the gaps in our bloom time. Look also for the things that have taken up too much territory. And we might tackle those two things, with those two ideas sort of in unison in the sense of: I’m going to make some room because the phlox has taken up too much. I’m going to reduce the phlox, and I’m going to think about what to put in that’s going to be a different time from the phlox or my irises and peonies and so forth.

And any other hints or aftercare ideas or anything else about the transplanting, dividing and the rest of the process?

Toshi: Well of course, when you do make those divisions, if you’re going to reuse those plants in another part of the garden you’re going to want to water in a ton as soon as those plants have been transplanted. So obviously nothing likes to be pulled out of where it’s living and then moved somewhere else without tons of care. So you’re going to want to, at the very minimum water in your plants, and watch them regularly to make sure that they’re still alive. I think…

Margaret: No, and I think what you said before about that fall has become the primary time that you’re doing this—that’s what’s great about fall also, is that some of the watering in, once you do it in the early going… Fall and winter in many climates like ours in the Northeast, for instance, or a lot of the Northern United States, will help you with that. Keep it moister until spring while it’s in that rooting-in period as opposed to doing it July 1st [laughter].

Toshi: Yes. And I try to avoid transplanting in the summer as much as possible for obvious reasons. Here, we’ve been going through a lot, except this year we haven’t, but come July the rain, if it comes, comes in 20ths of inches as opposed to the inches that we want.

So one great thing about plants and transplanting them in the fall too, is they’ll keep rooting until the ground freezes, and the ground freezes much later than one would tend to think here. So at some of my previous jobs, we bulbed until Thanksgiving, and transplanted and all that kind of stuff. And for the most part, plants come out fairly well the next season, the next spring, so. [Above: A view north over the reflecting pool toward the arborvitae allée. The clipped yews framing the pool are backed by by looser plantings of Syringa reticulata and Viburnum sieboldii.]

Margaret: I wanted to hear, you’ve had with the coronavirus lockdowns and people wanting to get out, last year you add a big uptick in visitorship, didn’t you, at Wethersfield?

Toshi: We did, yes. We had seen a couple of thousand visitors per year in normal times. And last year, people were so eager to get out of their house, and we were open to the public. We opened for free, because we didn’t want to have any contact with anybody, exchanging money or something, handling money. Nobody knew anything.

So we opened for free and we wore masks and we asked visitors to wear masks, and we had maybe 10,000. So our visitorship multiplied on a scale of like four or five, or maybe even more, and it was great. So we had an introduction to a lot of new people, and we started a membership program, and thinking about how to address larger-scale visitorship. But these are all great problems to have.

Margaret: Totally, when you’re doing the work that you’ve been doing. So just in the last minute or two then, fall highlights. So you’re open through September, through the end of September I think. And it’s by reservation. What are we looking forward to coming to see? What are some of the highlights of the later August into September dates?

Toshi: So a lot of our… Do you mean programmatically or in the garden?

Margaret: In the garden, yeah. What would I see if I came for a walk?

Toshi: So the unique part of Wethersfield is its formal gardening. We have a pleached beech tunnel, we have amazing topiary. There’s an aerial hedge of little-leaf linden. We have terraces filled with container arrangements. The gardens around the house have historical collections of fuchsia and begonias and pelargoniums in containers. And I’ve just been trying to edit the beds to do as much work, matching the colors of the fuchsias and the begonias, so that we have an overall feeling when you enter these rooms that have the flowers. [Above, the Italianate landscape is defined by its clipped yew, its collection of trained and cultivated European beech and more formal elements.]

We also have a 190-foot allee of arborvitae that has an end point of a naiad fountain, which is pretty spectacular. And there’s a beautiful rill and some radial steps. And it’s just really a very unique garden in America, filled with features that you would tend to see more in Europe than anywhere else in the country.

Margaret: Yes. And being lovingly tended back to prime form by you and your team. Toshi, I know I’m so glad to speak to you and I’m going to come visit soon. I know that that’s overdue, but it’s great to tell people about this—and thanks for the advice on how to get started with some of our editing and dividing, and I’ll talk to you again soon, I hope. [How to visit Wethersfield.]

Toshi: Well, thank you so much for having me. I love your podcast and your newsletter, and it’s such a pleasure to speak with you.

(All photos by Toshi Yano.)

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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 Aug. 23, 2021 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).

  1. What a wonderful interview! As informative and interesting, as it was a treat lovely on this yet again rainy NE day. I can not wait to visit this magnificent garden. Thank you, Margaret.

  2. Sandy Lentz says:

    “flocks”? Maybe “phlox”? Made me smile, and think about an article I read just yesterday about sheep in the English Lake District! I enjoy your Sunday posts, though I do wish your most current NY Times piece would be available along with the others. I subscribe to the Times but your columns don’t seem to show up in the National edition I get in Oak Park, Illinois. Or do they appear on Sundays, which paper I don’t get – too busy to read all the interesting stuff.

    1. Mary Hoblit says:

      Very enjoyable. I had lost touch with Margaret Roach. Scriber to her Newsletter several years ago it was glad to catch up with her again.

  3. Ann says:

    It took me about 2 hours (with lots of breaks) to divide up one of my old grasses in May! I wish I had a chainsaw at the time. I made about 5 plants out of it! With hostas I use my hands too to break up the roots. Very lovely interview! Hope to see that garden some day!

  4. kassie says:

    I visited Wethersfield something like 20 years ago when it was limping along, and I loved it’s “forgotten” ethos, but now I can’t wait to go back! Thanks for a great interview.

  5. Mary says:

    What a pleasant podcast! Being in the end-of-summer lull, this motivated me to start planning for what I will need to plant this fall by looking for blank spots in the gardens. Thanks!

  6. Heidi Husnak says:

    Great as always. Big fan of the serrated bread knife here. What an interesting space your guest has to work with and I admire his thoughtful process.

  7. Nancy V Klein says:

    I am relatively new to gardening, and your podcasts are like your favorite friend who is a master gardener coming over to give you advice and encouragement. Thank you for this gift!

  8. Tibs says:

    Definitely want to visit that lovely estate garden. And I hate to say how I divide my clumps of perennials. You’re going to cringe. With my heavy duty shovel. Position where I want and jump down on it. Then scoop the plant out. Works great on phlox, Siberian iris, and other thugs. The phlox are on their annual attempt to take over the world. Perfect balance this year but if I don’t go after them this year….

  9. Elizabeth Thompson says:

    Thank you so much for this article. Being a well-established Gardener for many years you taught me a lot. God bless you and yours always looking forward to the newsletters

  10. Kathy in Westminster, CO says:

    Question: I noticed some 3 year asiatic stalks with bulbs pushing out of the ground. Can I dig those now and replant them while the foliage is still green? Colorado has such temperamental weather. We could get an unexpected, early snow and freeze followed by weeks of nice weather. I could also mulch them until the foliage dies back. What would you do? I have time now. Also, wonderful information. My sister used to live in Albany and we came to visit every year. I’m going to ask her how we missed this garden.

  11. Jeanette Polanski says:

    The link to “The Well Tended Garden” is broken.

    I absolutely love listening to this podcast as well as reading the articles in the New York Times. Thank you tonnes!

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