be a discerning shopper for native plants, with uli lorimer

AS MORE GARDENERS shop for native plants each year, more plant descriptions in catalogs and on nursery labels use the blanket phrase “pollinator-friendly” to catch our attention. But is that the whole story behind each plant that’s so labeled, and how do we choose among the many named coneflowers or asters or heucheras, and figure out which one doesn’t just look prettiest to us, but does the best ecological job?

How can we each become more informed native plant consumers? I asked Uli Lorimer of Native Plant Trust, who has made a career of working with native plants. He was longtime curator of the Native Flora Garden at Brooklyn Botanic Garden, and in 2019, he became Director of Horticulture at Native Plant Trust, the former New England Wild Flower Society and America’s oldest plant conservation organization, founded in 1900.

We must learn to “think holistically and not just from the human’s perspective. Like not, ‘What do I want my garden to do for me?’” says Uli.

We also talked about Native Plant Trust’s extensive education program—including a full list of online courses in native-plant topics from garden design and gardening for pollinators, to plant identification—even one called “Native Species, Cultivars and Selections: What’s the Difference?” that Uli is teaching July 17.

Our discussion ranged from the genetic difference between patented or trademarked plants compared to the straight species nature created; about why we consumers should ask whether chemicals such as neonicotinoids were used on them, and more.

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Plus: Enter to win a ticket to that July 17 online class by Uli that I’ll buy for one lucky reader by commenting in the box at the very bottom of the page.

shopping smarter for native plants, with uli lorimer


Margaret Roach: How has spring been?

Uli Lorimer: It was good. I mean, in the sense that it was a very strange year without the public here and unfortunately we weren’t able to open until a little past the peak for our spring displays. So on one hand it felt very privileged to be able to see it and have the whole garden to yourself. And on the other hand, it certainly felt like a shame, not being able to share it with our members and the public.

Margaret: And you’re all able to keep working, you’ve been able to stagger people and do all that to keep the garden going?

Uli: Yeah, we’ve been very fortunate that we’re in a good position financially this year, and with some creative scheduling and getting to work on some work-from-home projects, we were all able to stay fully employed.

Margaret: Oh, I’m so glad to hear that. Not the case everywhere, but very good news.

Uli: Yes, we certainly are very fortunate.

Margaret: So before we begin our main topic, I just want to say, I mean, so many people have been looking for online opportunities to learn more. And native plants are such an important subject, and a subject that’s in demand and desire from so many gardeners. And you guys have a lot of great courses, I just thought you could give us a couple-of-sentence pitch about those, and then I’ll get the link with the transcript of this show to where people can browse the course listings and so forth, and maybe register for one.

Uli: Yes, absolutely. So public programs and education is a big part of what we do. And so we offer two certificate programs, which are designed to get you through sort of a basic certificate in ecological horticulture and botany and field ID. And then there are also advanced certificates in botany and conservation.

In addition to that, we also offer a wide variety of classes and field studies, almost all of them now online, of course, because we still can’t have classes in person. but touching on everything from design, basic gardening for pollinators, plant families sorts of things, gardening for plant diversity, plant ecology. There’s a whole slate of courses that are there, and I’m sure that there’s something for all of your listeners.

Margaret: Oh definitely, and including me. [Laughter.] Very tempting lists. Well good, thank you for that synopsis, because it’s great stuff.

So I confess, Uli, I feel like I know a medium-intermediate, or advanced-intermediate amount about native plants, for a gardener—for someone who’s not a scientist or an ecologist or whatever. But I confess that even I am totally overwhelmed a lot of times. And I said in the introduction, the coneflowers, like I think there are nine or 10 species in nature of Echinacea, but now there’s like a zillion named coneflowers in the garden center. And then I read stories with headlines like “12 of the Best Echinaceas to Grow,” and it’s like, “Help!” You know?

Maybe we should begin with a sort of explanation of what’s a straight species, what’s a selection, a cultivar. Kind of a 101 on what are all of the sort of versions of what we’re seeing of native plants as consumers, yes?

Uli: Let me begin by saying, I completely agree that the amount of choice is bewildering. And even for professionals, it’s hard to sort out all of the different options that are out there. And I can certainly see as a home gardener or somebody just getting into interest in native plants, that it’s really hard to figure out where to begin.

So to answer your question, we can define species of plants as plants that have evolved with a sort of distinct suite of characters that includes geographic distribution, their morphology, the way that they look, and increasingly some degree of genetic distinctiveness. And they’re naturally occurring. So these are things that humans have not had any direct hand in creating. And there are a couple sort of sub-levels that people might encounter that include subspecies and varieties and forms, and these are things like the pink-flowered dogwood, for example, that may occur in nature every so often in a population of white-flowered dogwoods, but stable enough that it gets to be called a form or variety. So there’s that.

Now, species can hybridize with one another, as long as they’re within the same family of plants. And so two classic examples are oaks and Amelanchier [above]. And oaks, we have a lot of different kinds of oaks here, and wherever their ranges overlap, there’s a chance that they can hybridize with one another. And so out in the wild, you find individuals that have sort of intermediary characteristics between, that show something from both of the parents. So you can have naturally occurring hybrids.

Then the next part of the definitions are where humans get involved, and that’s where we begin to make hybrids of plants that would not normally meet in the wild. A great example would be…  I think one of the more well-known hybrids to come out of my former employer, which is the yellow-flowered magnolia, Magnolia x brooklynensis. So that was taking a magnolia from eastern North America and introducing it, with full consent [laughter], to a magnolia from eastern Asia, and then looking at the progeny of that cross and selecting certain individuals for, in the case of the yellow magnolias, we were looking for yellow flower color and later bloom time, so that there would be less of a risk of frost damage in the spring.

And so to come out of that are named cultivars like Magnolia ‘Elizabeth,’ or ‘Hattie Carthan,’ just a couple, to name a few. So again, this is human hands creating something for the purpose of wanting a different color or to minimize the risk of frost damage.

Then basically, selections then fall into the category of, I’m walking out in a nice meadow in the fall and I’m looking at a field full of little bluestem. And I notice one individual that has just strikingly blue foliage. And so I collect seed from that and I grow it, and if it’s stable and continues to produce that blue color, then I can give it a name and I can patent it. And it becomes a selection, or a cultivar, of a native plant.

Margaret: And that’s even done, I always use the example, even in like tomatoes. A ‘Brandywine,’ I say, is not a ‘Brandywine,’ is not a ‘Brandywine’ because if this seed company and that seed company and the other seed company, if they’re all seed farms—if they are growing it on and growing it on, generation after generation and saying, “Oh, this one has the biggest fruit or the most fruit or the most disease resistance or fruits earliest.” And they’re selecting their seed crops for subsequent years from those fruits, right? So it’s not just with native ornamental plants or native plants used in ecological landscapes, but this is with plants, yes? We can make selections. We’re not interfering, we’re steering. I mean, we’re not crossing, we’re steering, I think. Yes?

Uli: And I think this also brings up a really important distinction is that, if you’re collecting seed from a parent plant and growing it from seed, you’re going to expect a certain degree of natural variation. And to your point, that a ‘Brandywine,’ isn’t a ‘Brandywine,’ isn’t a ‘Brandywine’ because if you’re growing it from seed year after year, there’s going to be mutations. There might be something a little bit different and you’re selecting for big fruit or particularly red skin, or whatever the characteristics are.

And the distinction I’m going to draw here is with plants that are patented. And so you see this also amongst the bevy of choices at the nursery, you see plants that have the letters PP and a bunch of numbers after it, or even a little sort of patented trademark. And so these things were registered with a plant patent office, and in order to be registered they have to be cloned.

This is a really important thing for your listeners to understand that any plant you buy that has those numbers on there or that’s patented is genetically identical to every other one that has that name.

Margaret: So it’s not produced sexually, it’s produced by cloning in a laboratory environment where little pieces, cells, whatever are replicated to make more plants, asexually. [Above, young plants in the greenhouse at Native Plant Trust’s Nasami Farm.]

Uli: Yeah, or they could be done through stem cuttings or root cuttings, but essentially cuttings; they’re cloned.

Margaret: O.K. Would that include tissue culture, laboratory propagation, is also … ?

Uli: Sure. I mean, some plants are difficult to propagate that way. And so we’ve overcome those hurdles with tissue-culture techniques, and lab techniques. And then others lend themselves to taking a stem cutting and dipping it in some rooting hormone, and there you go. And off it goes. But so the important part here is that there’s low genetic diversity in patented plants and they have to be cloned asexually in order to receive the patent.

Margaret: So I’m inferring then that low genetic diversity is not the way nature intended it, is that correct?

Uli: Yes. I mean, part of what makes … so to get to a really fundamental point here: Plants cannot get up and move if conditions become tough. They’re literally rooted in place. And the only way they can move around is by seed dispersal. And so, because they’re stuck in place, that they rely on adaptability to survive. And that adaptability, the core principle behind adaptability is genetic diversity.

The more diverse the genome, the more likely it is to develop novel mutations that lead to survival. So it’s very clearly stated that plants with lower genetic diversity don’t have as much of a chance in nature to adapt and change.

Margaret: O.K. So you’re a native plant person with a lot of expertise. You’ve made gardens and consulted, and probably advised people and written about it and spoken about it. When you go shopping—if you took me shopping and I was bewildered—what would you want me to get about this? In that sort of, I’m looking at tags, I mean, is any of this, besides the patent number or the PPAF or whatever it is on the label, does it hint at it? How can I be a smarter shopper? And also, which of these things are better or worse from Uli Lorimer’s point of view as a native plant expert?

Uli: Well, so there are two big questions here, I think. One is, if you see a name in single quotes behind the botanical name, if you’d like, then it is a cultivated variety. If you see a sort of trademark name, let’s say you’re in the market for Baptisia and you see Twilite series and a little trademark, and then another name in single quotes. That means that these are human-created plants, which is not to say that they should be avoided altogether.

And I think this is part of the conundrum around this particular issue—there’s not enough information out there right now to really make informed choices. And so there’s a lot more research that needs to be done. And we can talk a little bit about people who have begun to address this.

And as you might expect, the answers are not linear. I mean, they favor species over cultivated plants in terms of ecological function and pollinator preference, but there are outliers.

The other big issue, I think, is that plant labels in the nursery don’t give you all the information you need to be an informed and educated consumer, and maybe that’s purposeful.

And maybe that’s part of what people need to ask is … you want to know how is this plant propagated, would be one question to ask your nursery person.

Secondly, were any pesticides applied in growing this plant? And I think that’s another aspect that people don’t think is important enough to ask. But if you want to be pollinator-friendly, regardless if you’re using species or cultivars, you can’t do it if your plants are soaked in pesticides.

Margaret: And so are we just talking about the neonicotinoids, the neonics, which are systemic chemicals that even I think are applied to the seed as well as in the plant once the thing is growing. I think there’s a couple of uses for them. And they’re persistent in the plant, even when you bring it home, yes? [Above, the bloom of Chelone glabra, turtlehead, being visited by a pollinator.]

Uli: Yep. They’re by far, I think, the Number 1 offender, but there are other products that people use to keep plants, quote unquote, bug-free so that they can look beautiful at the nursery.

So, I think the issue about genetic diversity, which we’re trying to kind of unpack and unfold here, is certainly an important one, but I don’t think as important as finding out about whether or not these plants were treated with neonicotinoids. You buy native plants because you want to support pollinators, which is a great thing, and everybody should do that. And you don’t want to find out after the fact that the plant that you bought indirectly or unwittingly poisoned the very things that you’re trying to support.

Margaret: Right.

Uli: So that’s certainly a really important question to ask. And again, if enough people ask it, if nursery managers, growers, they’ll have an answer for you, or if they don’t, then perhaps it’s time to look for another place to shop.

Margaret: Right. And a lot of them are proud to display the information saying that they are free of neonics. I mean, the ones who have been getting ahead of it, I think. Because if you do that, if you make that commitment as a nursery, you should showcase it, because it’s a perk; it’s an extra dimension of desirability for a certain consumer, right?

Uli: Yeah, absolutely.

Margaret: There’s so many, you mentioned series and so forth. And there are so many series and a lot of perennials and so forth, and sometimes they look too good to be true to me. Like the flowers are too big, or too double. And I’m suspicious that they’re sterile, maybe, they’re not usable mechanically by the insect that might’ve used the straight species.

Is there sort of this misfit thing that plants are bred—I know that there is—plants are bred for my eye appeal as a gardener, but don’t match the needs of the original insects who co-evolved with the original species. I mean, like Mt. Cuba Center in Delaware and other places, University of Chicago have done trialing to see whether that’s true or Dick Lighty—excuse me, not Dick Lighty who was at Mt. Cuba years ago—but Doug Tallamy of the University of Delaware has research teams exploring the insects’ utilization of cultivars, or he would call them nativars, versus the straight species. So is that another part of this that you worry about, I assume?

Uli: Yeah, absolutely. I think that still the driving factors for the creation of this bewildering array of choices is aesthetics. And it’s based sort of broadly on consumer preference, which sort of the top things that they like are what could be called “novel flower morphologies,” or double flowers. And there’s a lot of double flowers. [Above, a double-flowered Trillium grandiflorum.]

And they may look really pretty, but if you’re swapping out the organs of the flower that actually make the nectar and the pollen for more petals, they serve nothing for pollinators and for insects. So that’s one extreme. And then being bred for a shorter stature, or bigger flowers, or longer bloom times.

It’s unclear, this is again one of these places where more research is needed, what effect that has on the quality of the floral resources.

And then to Doug Tallamy’s point that when you begin to breed plants with drastically differently colored leaves, the insects that feed on those don’t recognize them either visually or they don’t taste the same as the straight green leaves that they’ve evolved to feed on.

Those are all sort of things that, in the pursuit of beauty in our eyes, we have changed these plants so that they’re less functional for these other relationships that they’ve evolved with. And that’s my concern with this big issue.

Margaret: Me too, and especially one you hinted at, which is the dwarf, that sort of making things smaller for average garden size, or that look good in a pot in spring—that they can make them bloom early in a greenhouse and then put them out so that we all want to take all of them home. And that doesn’t necessarily suit either a longterm garden plan, frankly, or the insects and other creatures who could utilize them.

I just wanted to ask you what other things you’d love—a couple of bullet points, whatever—that you’d like to make sure that we have in mind when we’re doing our homework and figuring out what we’re going to shop for, especially for this summer for fall planting and so forth.

Uli: Yeah. I mean, I think more broadly, to think as holistically as possible with your garden planning and that the garden is not just for you, it’s for all the other organisms that rely on these plants for food, for shelter, for forage. There’s all of these wonderful relationships. I think most people want to see a garden that is alive with life. [Above, a Baltimore checkerspot butterfly chrysalis; below, its caterpillars. Adult is at top of page.]

And so to think of your plant choices as being driven by what’s best for all of them. I think it’s one of these things is that you can have your cake and eat it, too. In other words, you can build gardens that are aesthetically beautiful and pleasing for us, but then also maximize the support that you can give to all these other organisms. And it’s not just insects, it’s the things that eat insects. It’s the way that all of this life is interconnected.

And so just sort of generally speaking, think holistically and not just from the human’s perspective. Not like, “What do I want my garden to do for me?”

Margaret: Yes, the food web.

Uli: Yes. And it’s, frankly, it’s depressing to talk about the losses of birds and insects and so forth. And I’d much rather focus the conversation about positive things that you can do to support the maximum amount of life in your little pocket, and hope that what you do connects with maybe what your neighbors are doing and that on the sort of local to regional scale, we can actually really make a difference.

And so I think inherently, it’s a very hopeful message. It’s not one that sometimes feels like we’re trying to tell you what you can and you can’t plant.

Margaret: Right, and to figure out what we want to plant, and what does those jobs best that you were just describing—that’s why we need to look on the Native Plant Trust website and at those course listings, because I think there’s a lot of information there for us to become more discerning choosers and users of native plants. I always love talking to you, so we have to do it more. [Laughter.]

Uli: Yes.

Margaret: Kindred spirit.

Uli: I greatly enjoy our conversations.

Margaret: So thank you very much., Uli Lorimer from Native Plant Trust, and I’ll talk to you again soon.

Uli: All right. Great. Thank you so much, Margaret.

(Photos except Amelanchier by Uli Lorimer, used with permission.)

enter to win a ticket to uli’s july 17 webinar

I’LL BUY A TICKET for one lucky reader to Uli Lorimer’s upcoming class called “Native Species, Cultivars and Selections: What’s the Difference?” which is being offered live online by Native Plant Trust on July 17 from 1-3 PM Eastern (or another course of equivalent value, if the winner cannot attend that one).

All you have to do to enter is comment in the box at the bottom of the page, answering this question:

What was the last native plant you added to your garden–or what’s the favorite one that you grow–and why?

No answer or feeling shy? Just say “count me in” or some such, and I will. I’ll pick a winner and get them their ticket after entries close at midnight Monday, July 13. Good luck to all.

  1. stacey traister says:

    No garden of mine is complete until I have a lot of Echinacea Pallida, Paradoxa and, Purpurea. Ultimately I would like as many of the species as long as they can survive in my hot humid climate. The last native I planted was Eupatorium Perfoliatum.

  2. Susan Panofsky says:

    Narrow leaf milkweed was a winner this last summer with, for the first time, clouds of monarchs and many caterpillars. I would like to plant a few other milkweed varieties as well as nurturing flowers.

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