I HEAR MANY TIMES each week from readers or listeners wanting advice about native plants—about pollinator plants, for instance, or making a meadow, or which woodland wildflowers to plant and how to care for them. Uli Lorimer has extensive experience with all of the above, and says the way to get to know native plants is to spend time outside among them, to observe them in their natural context. An adventure in field botany, he says, can inform your practice of horticulture back in the home garden.

Uli Lorimer has made a career of observing and working with natives. He was longtime curator of Native Flora Garden at Brooklyn Botanic Garden, and recently, became director of horticulture at Native Plant Trust, the new name of the former New England Wild Flower Society, America’s oldest plant conservation organization, founded in 1900.

We talked about matching plants to habitat, of course, but also why evaluating their habits–do they spread by rhizomes, or are they clumpers?–is key, too, among other considerations. Not all goldenrods (or milkweeds, or fill in the blank) are created equal).

Read along as you listen to the June 3, 2019 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Spotifyor Stitcher (and browse my archive of podcasts here).

getting to know native plants, with uli lorimer

Margaret Roach: Congratulations on your recent change of job, Uli, and-

Uli Lorimer: Thank you. Yes, it’s very, very exciting times.

Margaret: Before we go on kind of a virtual walk among the wildflowers together, tell us about the new job and the new name for the former New England Wild Flower Society.

Uli: Sure. The organization made the first moves to change the name a couple of years back, and it was kind of in recognition that while our old name was very well known, it was sort of hurting us in the sense that it didn’t fully convey the breadth of the work that the organization does. And that even sort of simple questions like, “Do you guys care about trees?” because we’re a wildflower society, are the kinds of things that we would get.

Margaret: [Laughter.]

Uli: And so, it was seen as an opportunity to kind of repackage and rebrand the organization in a way that will hopefully reach a wider audience.

And in a way, kind of comes back to the earlier roots of the organization, in that we are primarily a conservation organization, that we also hold native plants in trust, for the public and for the future.

Margaret: And you do that, holding them in trust, in the literal sense—do you do that at your sort of headquarters, at Garden in the Woods in Framingham, or … Tell me about the “holding them in trust.” [Above, a path at Garden in the Woods; Dan Jaffe photo.]

Uli: Yes. So, the organization is … I like to use the analogy of a three-legged stool. Essentially, each leg supports the organization collectively. You’ve got conservation, you have horticulture, and you have education and public outreach.

And so, as I said, we are, at our core, a conservation organization, and one of the things that we’re most proud of is that we maintain a seed bank of the rarest of all of New England’s plants, and we’ve been engaged in monitoring populations of rare plants in every county of New England for over 30 years now.

Margaret: O.K.

Uli: So, quite literally holding the actual genetic resources, in terms of the seeds, here on site.

Margaret: Yes. So when we spoke the other day, kind of before this show segment taping, you know, you said a couple of things that really stuck with me. You said, “The best way to learn about all these plants and the full depth of diversity is to spend time outside.” And you also said, “Observations in context in the wild can help you be a better gardener.”

Let’s talk about that, because you’ve been an expert in this field for a very long time. So you have training, and you know what I mean, you have a lot of other things going for you in your insights, that fed your insights.

Uli: This kind of approach actually started, or began to really crystallize for me, when I arrived at Brooklyn Botanic Garden many, many, many years ago.

Margaret: [Laughter.]

Uli: And I thought that, you know, the best way to learn about native plants, to figure out how to grow them horticulturally, what kind of conditions they need, would be to observe them in the wild and see where they grow naturally.

And so, partnering at the time with the garden’s botanists and taxonomists, seemed like an obvious move. They could take me to places out in the broader landscape and show me where these plants grew, and then I could make observations about the kinds of plant communities that they existed in, the cultural conditions—you know, how wet or dry the soil is that they prefer, how much sun exposure, what are the underlying soil characteristics—and then use that information in a garden-sense to basically site, select, and grow the plants better with minimal input.

We don’t want to put a plant that likes really, really wet conditions in a dry spot and then end up having to water it all the time just to keep it alive.

Margaret: You know, it’s funny, when you said those things the other day, and what you’re just saying now, I think about the first time I sort of met the place where I garden, 30-something years ago, this couple/few acres inside or kind of mostly surrounded by an old state park, a forest area, and I remember seeing, especially at the perimeter of the forest, I remember seeing certain … I guess, now, I didn’t know then what they were, but now I would say plant communities. And you know, even today, they’re still there and they’re not anywhere else on my property. Do you know what I mean?

Uli: Yes.

Margaret: [Laughter.] They’re there and they’re there.

Uli: Right.

Margaret: They don’t jump 100 yards in the other direction, in more sun, or drier, or uphill, or downhill. They’re in the place that they’re in.

Uli: Yes. And I think that’s the sort of arc of this kind of … this approach, in terms of learning to be a really good observer, usually begins with looking at specific species and saying, “Well, I’m really interested in…” let’s say, turtlehead, Chelone. And so you go to places where it grows and you say, “This is great and I can begin to expand it out.”

After a while, you also begin to recognize the different kinds of habitats. You know, maybe first, more broadly, is it a grassland, is it a meadow, is it a wetland, is it a marsh? And then, as you visit more of these places and spend more time to, if you’re inherently curious, like I was, you begin asking those questions of like, how did those plant communities get there, why are they there, are they likely to go anywhere anytime soon, and what are the forces behind that distribution?

Margaret: So, you take those insights then, back to… in the places that you’ve worked; you worked at Wave Hill, I think, as a woodland gardener, another public garden in New York City. And then, at Brooklyn for all those years as a curator. You take those insights back with you from these wild places and you try to then create gardens based on those insights.

Uli: Yes, and I think that … so, it helps you to sort of predict, reasonably well, how those plants might behave in a garden setting. But it also, I think one of the really key parts of this approach, too, is understanding that disturbance on a landscape is a really powerful force in shaping the way that plant communities … what they look like and where they’re distributed. And that recognizing that gardening, in all of its shapes and forms, is a form of disturbance-

Margaret: I knew that’s what you were going to say. [Laughter.]

Uli: Yes. Whether you’re like … it’s sort of, do you cut your weeds off and leave the roots in place, or do you pull them up? And what happens when you pull them up? You introduce seeds from the soil seed bank to the surface, and there you have more weeds again.

And so, the idea that disturbance and succession are tied into the way in which plants behave is really powerful knowledge for a gardener because not all native plants are well suited for all kinds of gardens. I think that was sort of one of the more powerful lessons that you learn. And it’s partly from observation out in the wild and it’s partly from making mistakes in the garden.

Margaret: Exactly. And you said succession, and so I think of this kind of little meadow thing above my house, and it’s really an unmown area [above]; it’s an area where, in the kind of small field above the house, that I mowed and mowed and mowed for years, I sort of thought, “Huh, I think there’s some little bluestem there, and I think there’s…” and I got to know plants a little bit.

And I thought, “Huh, I wonder if I could time my mowing to favor some of these desirable things that are native and might be beautiful and good for the diversity here,” and so forth.

And so, I did, except, guess who wants to jump in and live there, you know, is for instance, some kinds of Rubus. I don’t know if they’re blackberries or raspberries technically, or what they are, but you know, things like that: woody, early invaders so to speak, successionally.

So, O.K., then Margaret thinks, in the first years Margaret thinks, “I’m going to pull that thing out with all my might.” And I’m getting crowbars, right, and shovels…

Uli: [Laughter.]

Margaret: And what is Margaret doing? What you just said, she’s making big holes where soil is churned up and all kinds of other creatures that are dormant in the soil and that seed in, right?

Uli: Yes, exactly. And it’s sort of that you can’t … and this kind of touches on another aspect of native plant gardening, is that people recognize some native plants are aggressive, or sometimes even called invasive. And it’s not their fault.

Margaret: [Laughter.]

Uli: Well, you know, because it’s easy to vilify invasives, because of the ecological harm that they cause. But for native plants that are aggressive, they’ve evolved to occupy a certain place in this arc of succession. And it’s usually the kind of things that want to move into your recently mowed field or open kind of grassland, an old agricultural land situation.

Margaret: Yes.

Uli: And if you can recognize that suite of species, those end up being really poor choices for a smaller garden, for example.

Margaret: Examples? A couple of examples of those types?

Uli: Yes. Mountain mints, Pycnanthemum, are really fantastic garden plants and support a wide variety of pollinators; they’re really, really beautiful summer-flowering plants, and some of them, like Pycnanthemum muticum, the broad-leafed mountain mint, or Pycnanthemum virginianum, the Virginia mountain mint, spread really aggressively through rhizomes, because they’ve evolved to try to colonize that open space while it’s still open and before the tree canopy fills in.

So, for a small garden, maybe that’s not a good example, a good choice.

A better choice that I found would be Pycnanthemum tenuifolium [detail above], which is the narrow-leaved mountain mint. It’s more of a clump-forming perennial and it more or less stays where you put it, it builds a larger clump over time. But is really unlikely to take over your whole garden.

Margaret: Well, it’s a good thing that was the one I chose last year to add to my little meadow experiment. [Laughter.] I mean, the meadow is bigger than a garden bed, but it’s not vast. So I didn’t want a thug. I didn’t want a thug.

You just used the invasive word. So, sort of to backtrack a second, you know, simply being native doesn’t mean that a plant suits your garden is what I kind of think I’m hearing you say. I mean, just because it’s in a list that shows that it’s present in your county or your state or whatever, doesn’t mean it’s good for you. Partly, maybe because it’s too ambitious, it’s one of these first invaders-

Uli: Early pioneer species.

Margaret: Pioneer species, right. Or it could be for other reasons that it’s not suitable for you.

Uli: Yes. And I think that’s what’s oftentimes missing in nursery information, for example, is that kind of successional status and like, what is this plant likely to do?

Margaret: Oh.

Uli: Another great example would be milkweeds, you know, we know milkweeds are really wonderful to support monarch butterflies. And the common milkweed has a reputation of being a thug in the garden. It’s perfectly acceptable in a much larger, broader landscape. It’s not going to invade into the woods because it doesn’t like shade. But there’s loads of other kinds of milkweeds, like butterfly milkweed, or purple milkweed, Asclepias purpurascens, that are better choices. [Above, aggressive common milkweed; top of page, better-behaved orange butterfly milkweed.]

That’s kind of the challenge for the home gardener, is you can look at a list of all the different milkweeds that grow in your area, and how are you to know which one plays nice with others and which ones don’t.

Margaret: So we need to be doing a lot more homework before … because not all milkweeds are created equal.

Uli: That’s correct. And so, you know, short of there being a good reference for that sort of information, you can gain that information by going out and observing these plants in the wild.

Margaret: So, with that, we double back to where we began, which is that we can draw inferences even as laypeople by seeing who’s taking over vast … I mean, in some places where I live, you see certain milkweeds in just massive expanses-

Uli: Yes, massive expanses-

Margaret: Right?

Uli: ... or Canada goldenrod is another example, too. And so, it’s sort of learning the plants, and I think that that exercise of learning the plants serves the purpose of really connecting you deeper with the landscape, with the cultural heritage that is associated with this region, with the biological heritage that is here. And then, it’s like seeing old friends, when you’re out in the woods, and you’re walking around, you’re like, “Hey, I know you.” It doesn’t seem so unfamiliar anymore. And then you can begin to put together why are they distributed the way. And there are so many wonderful garden plants that are out there, but they have to be put in the context of how they evolved.

Margaret: So, the goldenrods that you’re mentioning, and you mentioned Canada goldenrod [above], and I had a big fear that I had it, and of course, an expert person came and said to me, “Margaret, you don’t have Canada goldenrod, you have five other species,” because again, Margaret over here didn’t stop and slow down and get out her handbook and her field guide and key them out. You know what I mean?

I just assumed. [Laughter.] Not a good thing. I wasn’t making careful observations that I think you’re encouraging us to do. And so, what about goldenrods? I mean, they’re such incredible plants in terms of the insect activity; they sort of entice so many beneficials. And so, but which ones do you love that do work well in gardens?

Uli: Well, I like the licorice-leaved goldenrod, Solidago odora-

Margaret: Odora?

Uli: Yes. It’s not very widely known in the nursery trade, but it’s again, a plant that stays put and it doesn’t really seed around very much. It has the added benefit that if you crush the leaves, they have this wonderful, pungent anise scent to them. They’re also among the earlier-flowering goldenrod’s that are out there.

Margaret: Oh.

Uli: And again, we like plants that stay put in certain situations, and then we have other plants that they’re O.K. if they move around a little more slowly. And so, licorice-leaf goldenrod is a good one because it’ll stay put.

Other ones like gray goldenrod, Solidago nemoralis, or early goldenrod, Solidago juncea, are shorter-statured selections in terms of species. So they’re not ones that are going to be 6 foot tall or taller. And they will slowly seed around, but they’re not going to spread quite as aggressively as Canada goldenrod, or giant goldenrod is another one that’s commonly found in old fields.

Margaret: So, I’m slowing down. I’m making these observations. What tools should I have with me to help me … to support me in becoming a more astute observer, because some of them will be these observations and these “ahas,” but it doesn’t probably hurt to have a little bit of expert help in your pocket or hand, right?

Uli: Or phone.

Margaret: What are some of the tools?

Uli: First, I think I should plug … the Native Plant Trust has an absolutely wonderful web resource called GoBotany.

Margaret: GoBotany, I love GoBotany. You know, I’m a big fan.

Uli: And so, GoBotany, it’s a web-based resource and they have both sort of simple keys, so even if you’re not a botanist, you can follow the prompts and get a reasonable list of what you might have-

Margaret: Of the characteristics of the plant. “Does it look like this?” No.

Uli: So, it’s sort of like, “Is it a tree?” No. “Is it herbaceous?” O.K. “What color flower does it have?” Like these sorts of basic things. And then, as you get more comfortable with it, and if you’re at a more advanced level, there’s also the technical keys that are sort of behind all of that work are also available as well. So there’s really something for people of all skill levels.

Uli: In terms of field guides, I really like Lawrence Newcomb’s wildflower guide-

Margaret: Oh.

Uli: The reason I like it, is again, the key is very intuitive and simple, but it also forces you to look at all parts of the plant and not just the flower. And that, again, it’s educational because you begin to recognize which plants have opposite leaves and which have alternate leaves, and which ones have hairy stems and which ones are smooth. And if you don’t have a flower, you still might be able to figure out what it is. So many wildflower guides are just keyed in on the flower itself. If it’s the wrong season, they’re not particularly useful.

Margaret: So, the Lawrence Newcomb guide as well. Do you use any apps? Are you electronic, digital, virtual? [Laughter.]

Uli: I don’t actually.

Margaret: Because you know so much.

Uli: Well, you know, but I also find that part of the exercise of going outside is to kind of unplug-

Margaret: Yes, let it go.

Uli: … and let go of the digital tethers that have gotten into our lives so much. And I’m also kind of old-school in being a bibliophile. So I like books-

Margaret: Yes, I love books, too. My field guide cupboard runneth over. But I do find sometimes I will take out my phone and I will snap a picture because I find that that helps me to do the ID later. Do you know what I mean?

Uli: Yes.

Margaret: As opposed to get all obsessed and using one of the apps, and hoping for cell coverage and all that kind of stuff, I’ll take a picture.

Uli: There are a couple of other web-based platforms that you could use if you do like taking pictures. You could submit it through iNaturalist-

Margaret: Yes.

Uli: And it’s sort of a community-based platform where other people can help you with identification. There’s also a really great sort of beginner and intermediate and advanced level plant identification groups on Facebook, for example [like this one], where people routinely post pictures of, “This is growing in my backyard and I don’t know what it is,” and then the crowd comes together to help that person out in terms of ID-ing.

Margaret: Yes, I’ll give, with the transcript of the show, I’ll give some links to some of those.

In the last couple of minutes, I want to just talk about Native Plant Trust again, where we began. I am a diehard user, as I said, of the database GoBotany tool. But you have these campuses that we could come visit; tell us just a little bit about what we should … should we come say hello?

Uli: Yes, please do-

Margaret: From wherever we are around the country.

Uli: Tomorrow, come this weekend, because the garden actually looks fantastic right now. All this rain has been really wonderful for all the plants. We’re headquartered in Framingham, Massachusetts, at Garden in the Woods. It’s a 45-acre botanical garden with trails and ponds and swamps and bogs and woodland gardens. There’s a lot of wonderful displays to be seen here.

We also run a retail and wholesale nursery operation called Nasami Farm that’s in Western Massachusetts, in Whately, that you can also visit to buy plants. We’re really moving toward trying to sell only plants that were collected [as seed] in the wild and grown from seed, and as locally as possible. That kind of ties back into that field botany, fieldwork angle that we started the show with, because it’s really important for us as an organization to promote local genetic diversity and to provide those kind of plants to the general public.

We also own and maintain five sanctuary properties in Maine, New Hampshire, Vermont, and Massachusetts, that have unique plant-community and land features. One of the reasons why we bought those properties long ago was to make sure that they would remain wild and protected in perpetuity. So those are other places to visit.

Margaret: So all good places to do a little field botany to inform our practice of horticulture back in the home garden where we began. Well, thank you so much. Uli Lorimer, I’m so glad to speak to you, and again, congratulations. I look forward to coming to visit and seeing what’s up over there.

learn more

• The Native Plant Trust website
• Classes and other native plant education
• The GoBotany native plant database
• Nasami Farm Nursery (plants for sale); photo above
• Garden in the Woods, 45 acres of gardens, trails and natural spaces

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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 June 3, 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).