WHAT MAKES a tree or shrub exceptional – something worthy of introduction into the nursery trade, and eventually maybe making its way into your garden? There are many pathways a plant can travel to get there, including one unique one from the Arnold Arboretum of Harvard University.

As part of its 150^th anniversary celebration in 2022, the arboretum announced its Arnold Selects program for identifying and launching such potential treasures, each with its own provenance or story to tell, inspired by the arboretum’s vast and historic living collections. I wanted to know what catches the eyes of the modern-day experts there and why.

I asked Chris Copeland, Manager of Plant Production at the Arnold Arboretum, who did his Bachelors, Masters and Doctoral degrees at UMass-Amherst. His role at the arboretum includes a focus on the Arnold Selects program that each year distributes extraordinary woody plant selections to nurseries that it partners with, in the hopes that more gardeners will in time come to know these special plants.

Read along as you listen to the Sept. 14, 2026 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 (and browse my archive of podcasts here).

the plants of ‘arnold selects,’ with chris copeland

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Margaret Roach: Welcome, Chris. It’s so interesting reading about Arnold Selects on your website and from what you’ve told me so far about it in preparing for this taping, because here we are in this era where shoppers at the garden center are sort of bombarded with branded plants, patented everything [laughter]. And the Arnold Selects program strikes me as something different, not quite so purely commercial mass-market venture-ish with fancy labels and matching pots with your logo printed on them maybe, but something more in keeping with the history and mission of the arboretum, which was always about plant exploration and knowledge and dissemination and education, wasn’t it?

Chris Copeland: That’s absolutely right. So what I love most about the Arnold, there are so many roles that the Arboretum provides, whether it’s to the public, to researchers, to scientists, but there’s so much genetic diversity across the 17,000 living specimens that we have. It’s so genetically rich, and any botanical garden is going to be filled with spontaneous mutations and Arnold Selects is a way to really highlight all of that beauty that’s around us, whether you’re in the woods or in another botanical garden. But we have so much to offer and so much to show our visitors that the Arnold Selects program just sort of funnels and refines the best of the best that we have, and hopefully sharing that with not just our garden partners, but also our members and anyone from the public that wants a little slice of plant exploration in their backyard.

Margaret: Long before the Arnold Selects program, the arboretum was responsible for numerous venerable plant introductions. I think a lot of people recognize the name ‘Arnold Promise’ witch-hazel, yes, an intermediate witch-hazel, or ‘Donald Wyman’ crabapple I think came out of it? Those are just two that are stuck somewhere in my addled brain [laughter], but I’m sure there’s many more that are also well-known plants and much-grown plants.

Chris: Yeah, we have over the years. I mean, there have been eras of plant introduction dating back to basically day one. Jackson Dawson was our first plant propagator. He was hired in early 1870s. The Arnold was formed in 1872. He was a big rose hybridizer. And so Jackson had a big push to hybridize roses.

A few decades later, Karl Sax and Donald Wyman, who were in the greenhouse facility, they were sort of rethinking introduction, rethinking what are the plants that the public wants? The public is interested in smaller plants for the modern landscape. So those two were really interested in dwarf varieties, which spanned a lot of different genera, a lot of different plants from forsythia, a lot of smaller dwarf shrubs. And that was a good chunk of our plant introduction came from those 20ish years of breeding smaller plants. Plants with pigmentation, a lot of pink flowers seemed like the big focus.

And then we sort of had a quiet period of plant introduction. And in the late ’90s, we started to really have that interest to reintroduce a lot of these plants that may have been lost in the nursery trade or maybe even lost in the arboretum grounds sometimes. And they have these plants that are sort of out there but not really promoted or disseminated. So in the late ’90s, there was a plant introduction program called PIPD; the mission was to really just promote and distribute these cultivars that were out in the trade.

Arnold Selects, as you said, formed in 2022, but it’s just to breathe oxygen back into that initial re-release program. So it’s a lot of these tried-and-true plants. And we’re just a few years into Arnold Selects, but we’re always thinking about the novel and new plant material, what’s coming through the greenhouse facility or what might be out in the grounds that’s just waiting to be selected and introduced at some point.

Margaret: And so speaking of where do the plants that you’re going to introduce get their start, some of them, as you’re saying, are straight from the collection in the sense that they’re things that maybe got a little lost, but they’ve been there [laughter]. And others, you used, I believe, the word “mutation” before. Are some of them chance mutations that you noticed on plants in the collection that then a colleague said, “Oh, that looks good. Let’s try to replicate that”? Because you’ve got a lot of genetics to work with there.

Chris: We do. The grounds needs to have this constant review, walk-throughs. We try to walk through, the staff does, and we really try to get eyes on what we’re seeing and share notes. There are so many people on staff that have a very keen eye for, “Hey, what is happening in the landscape?” But I would say one of our best examples, and one of our oldest examples of mutations in the landscape, is going to be the ‘Prostrate Beauty’ Korean fir [photo above], which is my personal favorite in the plant introduction history of the Arnold.

So Korean fir, Abies koreana, initially collected by our plant explorer, Ernest Henry Wilson back in 1917. So he actually collected Korean fir from Korea and brought it to the West through the Arnold back in 1917. We had this handful of Korean firs growing in the arboretum for a number of years. It wasn’t until, I’d say the late 30s where someone discovered, hey, there’s actually a horizontal branch, just one spontaneous growth, an offset, that had some really compact internodal growth. So a very dense branch that looked really different from the rest of the tree, the rest of the specimens that came from this seed lot in Korea. And that cutting, that branch was isolated, taken as some cuttings, and they were stuck in the greenhouses around 1940, and that trait was stable. And that’s a big part of going and pushing a plant forward and really evaluating, hey, is this a stable genetic mutation or is it just an environmental fluke? Which sometimes it is. That happens—variegated leaves happens all the time.

Things can come and go, but this was a very stable procumbent growth form. It was very unique in comparison to a straight-species Korean fir, which is a large upright tree. It’s got this really imposing stature, like any large conifer, a beautiful pyramidal form. But this ‘Prostrate Beauty’ as it was deemed early in the mid-20th century was such an opposite form. It was growing along the ground, compact growth, very dwarf habit, but all the features of a Korean fir that we love: the dark green evergreen needles, the classic purple cones, the hardiness; a very hardy plant, of course, I believe Zone 5. But it all traces back to this wild collection. We’re getting this buckshot of genetics. So every seedling is going to be a little different from its sibling, and not every plant is going to have such a distinct aesthetic difference to what its true species expresses itself as.

But ‘Prostrate Beauty’ proved to be a really stable form. We just have a few in the landscape. In fact, I believe the original 1940 plant is no longer in the landscape, but there were some clones taken and grown out in the ’60s, and I’d say the best ‘Prostrate Beauty’ in the collection at the Arnold is right along Conifer Path. It was an accession from 1967, and it’s our oldest. It’s about 60ish years, and you can really just appreciate how much space does this plant take up. It’s a really, really small plant. It’s maybe 5 feet by 5 feet. It’s a really, really nice, compact, hardy plant, and just the color, as you know, if you have ever seen-

Margaret: I do. I have a couple of conventional Korean firs, and I’m totally in love with them, and they’re big. I’ve had them for decades, and those purple cones, there’s nothing like it [above, the cones at Margaret’s]. I mean, it’s just mind-blowing every time they produce them. But the idea that there’s a prostrate one is just…I had no idea. And you’re saying that it’s not new, it’s something that’s been around, and you’re now promoting it as part of the Arnold Selects program, which is brilliant. And so to do that, do you give propagation material to partner nurseries, or what do you do?

Chris: We do. So we have a handful of partners. Arnold Selects was formed in 2022, and I actually came on board to the Arnold Selects program the following year, so 2023, and every year has been pretty consistent. We have a handful of partners—gardens, nurseries from around the Northeast and one out in Ohio. So we’re always looking for cold-hardy-climate nurseries to really stress-test these plants. But Broken Arrow is a partner down in Connecticut; Cricket Hill, which is down in Connecticut as well. Tranquil Lake, which is in Rehoboth, Mass. Weston Nurseries, which folks may be familiar with here in Massachusetts as well, Pleasant Run, and Heritage [Heritage Seedlings and Liners, in Oregon]. And Brotzman’s as well. Brotzman’s is a huge nursery, and Tim is a great grower out in Madison, Ohio.

Margaret: I have plants from Brotzman’s because my best woody plant nursery in my area buys a lot from Tim. So yeah, it’s all a hand-me-down big cycle of plant sharing in the world, isn’t it? [Laughter.]

Chris: Big time. And we always have a publication. If we’re going to re-release a plant, whether it’s from the 1910s or the 40s or the 60s, we always want to go back and make sure we have a full plant profile. It’s usually something that might be published in literature, so in an Arnold Arboretum magazine, “Arnoldia,” a newsletter. It could even be a peer-reviewed journal, but we want to at least have a profile of the plant.

What are the maintenance requirements? What does the propagation look like? That’s a huge part of introduction is, sure, you want your plants to be predictable, reliable, stable, but also propagatable. Tim wants to know that he can take these cuttings and produce a large quantity of plants and have a recipe really to produce plants in a predictable way. So the propagation protocols is a big thing that we try to refine, we try to crack that code: What is the easiest way to produce these plants, always clonally, but hopefully by cuttings if possible, which means that plant will be on its own roots and there’s no rootstock to really confuse a horticulturalist. But it’s all a package that we try to provide to our nursery partners.

Margaret: So we just mentioned that Abies koreana, which has this unusual habit for a Korean fir. What qualities do you have an eye out for in the 21st century? I mean, there’s a lot going on in horticulture [laughter]. Is it aesthetics? Is it resilience in a changing climate? Is it native-focused? Is it fill in the blank?

I don’t know, but I noticed that in these first few years of Arnold Selects, that there have been some natives in the program. I think there was a red maple, a sand cherry [photo below of Prunus pumila var. depressa ‘Gus Mehlquist’], an inkberry—an Ilex glabra  [photo above]. So I don’t know, is that something that you’re looking at? Because obviously there’s a lot of appetite right now for native things as well; things that, again, have resilience. I don’t know. Is it just aesthetic people? Are they still looking for smaller cultivars? I don’t know what the things are that you-

Or are you just looking at the collection and saying, “These are exceptional and we want them to be out there?” I mean, what are the hallmarks of something that catches your eye?

Chris: It’s a great question. And here in the greenhouses, we’re producing plants for the living collection, so we’re always bringing in wild material. Sometimes it’s the first time a species is in North America and we’re thinking, “Hey, how does this plant grow in Boston, Massachusetts?” So whether it’s for introduction into the nursery trade or just being introduced into the living collections here in Boston, I’m always looking at how is this plant performing under the intense environmental stress of Boston, Mass., whether it’s our really hot and humid summers or our really cold and dry winters.

All of our greenhouse staff are evaluating these seedlings, and the Arnold at the end of the day is a tree museum. So we want to produce plants that are here for the long haul. We want to produce centenarians, plants that’ll be here for my children’s grandchildren, hopefully. And so that’s baked into our processes. We’re growing plants out in an in-ground nursery, these small seedlings. We are evaluating how they’ve performed through a full growing season, how they’ve performed over winter, how they’re performing based on the intense disease pressure that the Arnold has. The Arnold is like Noah’s Ark, where we have two of everything. And so with all of that species richness, we have a lot of richness in pathogens and disease pressure.

Margaret: Sure, sure.

Chris: And frankly, that’s O.K. We want to have that stress test. We want to call out what are those plants that will be maintenance sinks for our horticulturalists, and for the introduced plants, yeah, what are those maintenance sinks to avoid when offering a plant to that nursery trade? It always comes down to that first point of performance and that hardiness of all forms.

And then second is that ornamental side. So that’s the visual, the mutation. So the performance is sometimes just invisible. It’s happening genetically under the foliage, under the wood, but it’s the ornamental side that really catches our eye sometimes first, sometimes before it goes through a first winter or a first summer.

And it could be a plant in the landscape, a witch’s broom that’s sending up dwarf shoots, or it just could be a seedling in the greenhouses that we acquired recently that is suspicious in a good way, sometimes in a beautiful way. What comes to mind is a cypress that’s in our plant production facility right now, just a few years old, a seedling from Oregon, Cupressus bakeri, and we’re growing out 10 plants, and this is for the living collections, really no conversations about introducing the plant, but we have 10 beautiful seedlings.

Most of them are upright and pretty predictable cypress trees, but one is totally pendulous. It has this crazy weeping form, and obviously that’s going to catch our eye. Sometimes it takes a year or two or a few months to really see those physical traits come to fruition, but we’re going to flag it. We’re going to put a little tag on that plant, put it into our database, make a note, and it’s on the list. It’s something that we’ll come back to. We’re always having a very careful conversation for what’s in the Arnold Selects pipeline, but first and foremost, how is it performing, and then what are those beautiful aesthetic traits that people want to see?

Margaret: Right. I mean, then there’s also the trying to predict the future [laughter] is part of a successful plant for the future, trying to predict its future behavior. So many of our older cultivars, horticultural varieties that became beloved garden plants, of course, then proved to backfire and some became invasives and so forth, and especially ones among the shrubs that fruited and the birds could carry the fruit around, and oh my goodness, and we ended up with a lot of disasters and things that used to be commonplace in everybody’s foundation plantings and hedging and whatever are a mess. So how do you look at that? How do you look into the future? I mean, is it like research or just…I mean, it must be a lot to think about.

Chris: It’s a lot to think about. It’s always a group discussion, but I think what matters most in terms of plant introduction is taking your time. We’re pretty fast in producing plants. We’re very good at propagation. We’re very good at transplanting and getting a plant from the seedling stage into the arboretum, but it’s taking the time to observe how that plant is performing. And that does start with the Dana Greenhouses, so we’re always observing what is the growth rate of a particular plant, something that we’re maybe growing that’s marginally hardy, something that’s from a different continent or climate that has never been introduced into Boston before.

So we’re always taking our time, we’re evaluating, we’re taking an annual census of our plants. We are revisiting all of our 2,000 plants in production and making these check notes. Sometimes we’re throwing a red flag up to say, “Hey, this young plant is producing seed at a very young age, and maybe we should really take it slow and before we plant it out into the landscape; let’s actually containerize it.” We’ll keep it confined so that we can just observe it for a few more years before putting it out in the ground.

Margaret: It’s fascinating to watch for the signals. I wanted to ask about a couple of the plants. One, I think 2024, I think it was, that it was an Eastern redbud, speaking of native plants, an Eastern redbud that I wonder if you could tell us about, because that was one of those mutation examples, right? Is that ‘Arnold Banner’?

Chris: Yes, that’s ‘Arnold Banner.’ Absolutely. So this is a great native to the Eastern United States, Cercis canadensis. This is a really interesting redbud. So it’s a plant that’s been in our landscape, I believe, since 2009, and it had this spontaneous white flowery mutation, which some folks might call these mutations sports, but it’s really a branch on the adult plant that’s performing a little differently. So it has a little less of the pink, but it is a white flower, but it has all of the right traits of our native species. [Flower detail photo above from Cricket Hill Garden nursery website.] 

So like you said, what are the trends that folks want to prioritize for their garden? And native plants, they have that familiarity, they have the performance, they’re tried and true, and that’s why it really was elevated to be introduced as one of our more recent introductions because, hey, this is a plant that it’s a smaller tree. It’s only going to grow about 20 feet tall in many years, not a fast grower. This is a very hardy plant, of course, Cercis canadensis, hardy to Zone 4. It’s pretty adaptive to a lot of different growing conditions, so it can occur in shade, it can occur in full sun, but it’s just a really tough plant, a tolerant plant. It has all the right things, but again, it just has that mutation of flower color, and ‘Arnold Banner’ just being a nod to the arboretum and the fact that this plant came from our grounds and it landed on our 2024 introduction list.

Margaret: It sounds exciting. So in the last minute, I just was going to say, I read in reading some of your CV and so forth, you’re into bonsai, too, is that correct? [Laughter.]

Chris: Yes, I’m the curator of our bonsai collection.

Margaret: So just because you can’t get enough plants, you also are into that. My goodness, that’s a whole other world.

Chris: It is. I mean, it does go hand in hand with Arnold Selects, and our bonsai has been in our collection since 1937. We started with about 39 bonsai as an original gift from Larz Anderson, and that collection has grown, of course, over the many decades. And for the past three years since I’ve been curator, I’ve been thinking, what is the identity of this collection? It’s a donated collection, so we always honor that original donation from Larz Anderson to Charles Sargent, our founding director.

And so there’s some great history to that, but bonsai is an art form that really celebrates horticulture. You can’t do bonsai without horticulture, without truly talented and refined horticulture. And so we’ve been trying to introduce some of these, some Arnold Selects, not quite formally yet, but what are the plants out in the landscape in the collections that tell an exploration story, whether that’s a Syringa reticulata, the lilac tree that was first introduced to the Arnold. So we have an air layer from an existing tree, actually the original tree, accession number 111A. So that’s going to be in our bonsai collection.

But the theme is really what is the Arnold identity and how can the art of bonsai really influence how we’re looking at plants? Bonsai are here for the long haul. I’d mentioned we’re growing centenarians in the living collections in the grounds, but our bonsai are frankly much older than that. Our oldest bonsai was started in 1737-

Margaret: Yeah, it really caught my eye. Well, another fascinating topic for a whole separate conversation [laughter] because I love them.

Chris: We’ll do it again.

Margaret: Well, Chris Copeland from the Arnold Arboretum, thank you so much for making time today to talk, and now go back and start eyeballing those plants and deciding who’s next.

Chris: Thank you, Margaret.

(All photos from the Arnold Arboretum website except as noted.)

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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 17th year in March 2026. 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 Sept. 14, 2026 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify (and browse my archive of podcasts here).