I LOOK FORWARD to spring for many reasons, not the least of which is the emergence and bloom time of the trilliums. There’s a saying that good things come in threes, and trilliums are certainly proof of that.
This spring I got to talk about trilliums, including the range of unexpected fragrances they possess, with Uli Lorimer of Native Plant Trust in Massachusetts, where they’re about to celebrate their 10th annual Trillium Week, and the organization is celebrating its 125th anniversary, too. We also talked about showing off tiny spring treasures like some of the miniature trilliums, or bluets (Houstonia) on what he calls “mossy patches” for a beautiful combination.
Uli is director of horticulture at Native Plant Trust, the nation’s oldest plant conservation organization, founded in 1900 as the New England Wild Flower Society. Uli, who is also the author of the “Northeast Native Plant Primer,” was the longtime curator of the Native Flora Garden at Brooklyn Botanic Garden before joining Native Plant Trust in 2019.
Read along as you listen to the April 28, 2025 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).
little things of spring, with uli lorimer
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Margaret Roach: I’m so glad to talk to you about things of spring.
Uli Lorimer: So pleased to be back.
Margaret: Lots going on there, huh? And lots to celebrate and enjoy, you guys.
Uli: Yeah, this is a big year for us. I think first and foremost, the 125th anniversary is a huge milestone for us, and we’re just so proud of all the things that Native Plant Trust has achieved in that 125-year period, and really looking forward to continuing our excellent work.
Margaret: I mean, the nation’s oldest plant conservation organization, that’s a pretty wonderful thing, and it’s had various names along the way, but it is the same organization. And I guess your home garden, so to speak, is in Framingham, Massachusetts.
Uli: That’s correct. That’s where Garden in the Woods is located, and if it had a birthday, it would be 94 years old this year.
Margaret: The garden?
Uli: Yes. So coming up on a hundred. Yes. The garden started in 1931 when Will Curtis purchased the property from a railroad company and started laying out the paths and beginning to enact his vision for this place to be a showcase for native wildflowers.
Margaret: Well, it’s a must-visit if people are in the Northeast. It’s a must, must, must visit. So there’s lots going on there in person. There’s also, you’re having your 10th annual, I think I said in the introduction, Trillium Week, and so that’s May 11th to 18th, and lots of special events around that in person.
Uli: Yes. And then we’re having an evening event on the 16th of May called Twilight Trilliums, and also kicking off a little before, at the beginning of May, we’re also hosting a native plant symposium called Join the Movement on May 3rd.
Margaret: And that’s virtual, so anyone listening can join that. And you have quite a list of speakers.
Uli: Yes, yes. It is completely virtual. And we’ve got Trevor Smith from Weston Nurseries. We have Edwina Von Gal from Perfect Earth, and Dan Wilder, who’s over at the Norcross Wildlife Foundation, and yours truly is the speaker lineup, so it should be some great conversations.
Margaret: O.K. So trilliums: They are well-named since all their parts, I guess come in threes.
Uli: Yes, yes. I mean, it was dubbed Trillium by Linnaeus in his attempt to describe the “threeness” of the plant, and it’s one of the, I think, most characteristic Eastern North American woodland plants that exists. And we have a really fantastic collection, an accredited collection, at Garden in the Woods.
But aside from talking about how to grow them, I also wanted to touch upon an aspect of trilliums that some people might not know, which is that many of them are actually quite fragrant.
Margaret: And that just surprises me, because as much as I’ve crawled around in the springtime soil [laughter] and bent over and enjoyed all these beautiful little ephemerals and all these little babies coming up, I never thought to stick my nose in a trillium and smell it.
Uli: And so just as a warning, some of them smell good and some of them do not. So we’ve been using a botanical key written by Alan Weakley, who’s at the North Carolina Herbarium, in his most recent publication about the flora of the Southeast. And since that contains the bulk of the diversity of trilliums, it’s a really great key to get familiar with, to figure out what all the different species of trilliums are. And there’s been a number of newly described species and new discoveries as of late, too. So we’re still uncovering more in the world of trilliums.
Margaret: Yeah, and when you say key, it tells how to differentiate one from another, how to sort of key them out?
Uli: Yes, so broadly speaking, we have trilliums where the flowers are called sessile [above], and they have mottled leaves. So the flowers sit directly on the plane where the leaves are. And then you have trilliums that are called pedicellate, because the flowers sit on a little pedicel that raises the flower either above the surface of the leaves, or in some cases of the nodding trilliums, the stalk kind of hangs below the plane of the leaves.
So this key is organized along those larger principles, and then it gets really into detail. The reason that I want to call it out is because one of the only ones that I’ve actually seen the fragrance written into a technical document, and I’ve highlighted a couple delicious ones here to share with you [laughter].
So there’s a species called Trillium delicatum, and when I think of delicatum, I think of the ‘Delicata’ squash, absolutely the first thing that comes to mind. But Alan’s key notes that it has a floral fragrance of horse manure.
Margaret: Oh, that’s delicate. Not!
Uli: [Laughter.] Right. Next in the couplet is Trillium reliquum, which is one of two trilliums that’s actually on the Endangered Species Act. So this is not one that you’re going to find available, and it shouldn’t be available, but he notes that its floral fragrance is of rotten meat. So really what that’s pointing to is a lot of these ones have those dark maroon flowers, and that their preferred pollinators are going to be the things that would be drawn to rotten meat or horse manure. So flies, fungus gnats, beetles—not pretty butterflies or anything like that. So it’s a pollination strategy more than anything.
Then we have another pair, Trillium decipiens and Trillium underwoodii, which have a yeasty-sweet, “similar to overripe bananas,” or yeast-sweet or “reminiscent of stale beer” as the fragrant notes. Really, you have to be able to stick your nose in on a nice warm day in order to be able to get some of these different notes.
Margaret: Isn’t there one that has a common name of stinking Benjamin, or did I just make that up?
Uli: No, not at all. No, you’re right. That’s actually one that grows for us here in the Northeast. It’s the Trillium erectum, which also sometimes gets called the wet dog trillium.
Margaret: I call it the wakerobin.
Uli: Yeah. Wakerobin is another common name that gets applied to a lot of different species, but he lists the fragrance of erectum as unpleasant and musty.
Margaret: Oh, sorry about that. That’s the one that when I came to my place many decades ago, that was in existence—that lived here already. Where I am located, that’s the one that I’ll see the most.
Uli: So on the other side of these maybe more unpleasant fragrances, two of the yellow-flowered trilliums, Trillium luteum [above], which smells like lemon; it’s actually really wonderful. And Trillium discolor has more of a clove-like fragrance. And so they’re really both wonderful woodland garden plants.
And then Trillium vaseyi smells like rose, which I think is really great, because most of the other ones are not so nice, apparently. But the backstory behind all of this is that at Garden in the Woods, we grow Trillium cuneatum [below], which is another one of these mottled-leaved and usually maroon-flowered species, but you can have petals that are maroon, bronze, green, or even yellow. So there’s a lot of different color forms, and so you don’t really know what you’re talking about until we decided to follow the fragrance key. And in this case, it smells like fresh green apples, or like Calycanthus, floridus if you know the Carolina allspice.
And it was such amazing way to be able to identify these particular trillium in the garden, just based on the fragrance. And it opened up this whole new world of appreciation for this plant that I didn’t know before.
Margaret: Wow. And you’ve known them well for a long time. You’ve been working with them for a long time, so that’s interesting. That’s a whole new dimension; that’s wonderful.
Uli: Yeah. I mean, there’s other ways to tell them apart, of course, but the fragrance thing—and I look at a fair amount of technical keys in my life, and there’s not very many that I can think of that include fragrance as a diagnostic character. So pretty neat stuff.
Margaret: Oh, that’s great. I always am looking—not right this minute, but shortly, once they’re kind of up and then they come into bloom and so forth—I’m always looking to see where I’ve got a good patch going, and maybe I can steal a couple and move them to somewhere else and keep my expanded territory thing that I’ve been doing for a long time, move them into new places.
And it’s really interesting for such a delicate little creature, when you dig one up for the first time, I think it’s startling to see what’s underneath the ground. If it’s an established kind of clump, there’s this knobby, gnarly, rhizome-y thing that almost looks woody or something [below, on T. erectum]. You know what I mean? It’s funky looking.
Uli: And kind of contrary to what most people would think, when it’s in bloom is actually the ideal time to lift them and divide them. Most people think, “Oh, I should wait until after the flowers are done or before it blooms.” But no, springtime is the active time. That knobby rhizome you’ll see has little bands on it if you look at it and inspect it closely.
Margaret: Right. It’s like ridged almost.
Uli: Yeah. So each one of those is what’s called a terminal bud scar. And so you can actually look at your rhizome, and you can count them almost like tree rings, to see how old that funky, knobby little rhizome is.
Margaret: Cool.
Uli: And some of them, something that might be the size of my thumb, could be 20, 25 years old. And that just completely blows my mind that this thing’s just slow and steadily been increasing for over two decades. And when you see a really, really big one, we have a couple clumps here in the garden that I think are probably 60 or 70 years old, and it’s just amazing to see.
Margaret: And even when you’re just getting started or a mature plant sets seed that the ants are grateful to move around [laughter]—and they march off to a new spot and you get some seedlings—it’s no time soon that you get flowers and the plant matures. There’s a lag.
Uli: Yeah. It takes from seed, about four to five years before you get something big enough to have maybe a smaller size flower. And then the really larger ones the better part of a decade.
Margaret: And that’s why I mentioned it because you just said, here’s this thing that 60, 70 years—I mean, for it to accomplish that it even has to go through this period when it’s not even barely above ground [laughter]. Do you know what I mean? There’s not even much of a plant, and yet it manages to accomplish this. It’s quite amazing.
Uli: It’s astounding. I mean, what I also love is the story that, O.K., you get to summertime and it gets hot and dry, and maybe the leaf begins to go dormant for the season. It’s not just sitting there underground. In fact, for most of summer and fall into when it gets cold, it’s busy using that energy it’s stored to form next year’s leaf bud and flower bud. And then it sits for a little period of dormancy over winter when things are cold and maybe frozen. And then as soon as it gets the right cues, that bud is ready to go and ready already fully formed.
So there’s this kind of tradeoff between how much energy can it store in the springtime, through its tripartite solar panel [laughter], and then how much does it have to spend to make next year’s solar panel?
Margaret: Right.
Uli: And I think about this, and it’s kind of a sad reality, but who really loves to eat trilliums?
Margaret: Well, I mean, I think deer do, but I don’t know who else does.
Uli: The deer do. And I think that’s one of the bigger threats to a lot of these is that they get munched when they’re above ground, and there’s no way for the plant to make another leaf for the season.
Margaret: Correct.
Uli: And so that’s a deficit in its energy reserves. And next year it’ll try again and the rhizome will shrink or get smaller. And if it gets eaten several years in a row, then that’s it, that trillium is done.
Margaret: So we have deer browse, we have invasion of invasive plants taking over more territory in the areas that used to have all of these spring wildflowers and so forth. And I mean, in some areas of the country, the feral pigs apparently are…because they just kind of churn up the soil, and forget the trillium’s ever coming back after that. So I mean, these are plants that are under pressure, under great pressure.
Uli: Yeah, no, absolutely. And there’s a lot of them that are considered globally rare because their national ranges are pretty constricted to specific areas in the Southeast.
Now, there are folks that are growing these and putting them for sale, A lot of folks growing them from seed, which as we just explained, takes a long time and accounts for how expensive they can be. But sort of as like a PSA for your listeners: Be careful if you find a place that’s offering bare-root trilliums like a bag of a hundred for really cheap.
Margaret: Guess where those came from?
Uli: Exactly. We don’t want to support folks that are just going out into the woods and ripping them off for a quick buck.
Margaret: Right, right.
Uli: So do your due diligence and make sure your vendors are reputable.
Margaret: Yeah. So when we spoke the other day on the phone as a preliminary thing to our conversation today, you talked to me about a way to use some of the smaller-scale trilliums and other little tiny springy, wild, woodland-y native things that I had never thought about really, which you called “mossy patches.” [Laughter.] And I wanted to just have you try to conjure that for people, and we’ll have some pictures with the transcript of the show, of course. What does that mean?
Uli: Well, so if you spend a lot of time in the same place and taking care of a garden, in particularly for us here in the Northeast, you go through this annual cycle of the leaves come out, and then the leaves come down in the fall. And then you either let them lay, if that’s possible, but sometimes you have to move them out of the way of a path or from smothering things.
And so sometimes it can be really difficult to cultivate what I would call “belly plants” or things that you have to get down to examine—really small, delicate little plants—because the leaf litter just simply smothers them or covers them up, and it makes it hard for them to grow.
And so the opposite of that is I began to notice that there were these patches in our garden where the leaves didn’t accumulate and moss was growing naturally there. Maybe it’s the way the wind blows or the way that we manage the pathways or the leaf litter that just kept leaves from accumulating there. It became this sort of aha moment, that if nature’s already keeping this spot clear of leaves, then why not take advantage of that and use it to display these really wonderful dwarf plants?
And I saw this, the first place that I saw this to really wonderful effect, was at the Mt. Cuba Center, maybe about a decade or more ago. And they had this wonderful mossy patch underneath of a dogwood tree at the sort of shady end of their wildflower meadow. And they had planted it with Houstonia, the little bluets or Quaker ladies [below], and it was just the most stunning sight. It was like a dusting of snow in May with this wonderful green, vibrant backdrop. And I thought, “Wow, that’s amazing, and we should do that, too.”
Margaret: Instead of condemning the moss and saying, “Oh, there’s moss.” Because that’s the other thing about moss is that some people disdain it. They think it’s a problem. Right.
Uli: And sometimes I see lawns around here that are a lot moss, and then people keep fighting the moss thinking that they could get their lawn growing, when what they ought to do is embrace the moss and reduce the lawn and plant other things.
Margaret: In the mossy patches.
Uli: Exactly.
Margaret: So some of the little trilliums, some of the smaller-scale trilliums?
Uli: So there’s two species that I think are really wonderful. There’s one called Trillium nivale, which is like a dwarf snow trillium. And then there’s a whole another group called Trillium pusillum [above]. It was a single species, they’re called dwarf trilliums, or least trilliums. But thanks to a lot of genetic work and broad regional distribution that single-species concept has been split into about 10 different varieties. And so there are things like one that’s called alabamicum that only grows in Alabama. There’s one that’s called carolina, which is along the Piedmont fall line in Carolina. There’s Trillium pusillum monticulum, which is in the mountains of West Virginia. There’s one called ozarkanum that’s only out in Arkansas.
So you can kind of get to see that they’re beginning to name these based on their locations. So it has this kind of funny range, but they’re a really wonderful species that would kind of get lost in a garden that had heavier leaf litter. And so they’re really ideal for these mossy patches.
I mentioned the Houstonias. Houstonia is another, that’s probably my most favorite one to put in there.
Margaret: At the edge of my property, you’re making me think of how from the very first spring I was here, and now even more: There’s moss because there’s a tree line and Maianthemum, the Canada mayflower, is that what it’s called?
Uli: Yeah, that’s exactly it.
Margaret: Maianthemum is intertwined in the moss, and it’s quite beautiful. It’s just this natural, these natural companions. Yeah. They is happy and beautiful together.
Uli: I like the Maianthemum. It has this wonderful kind of round leaf, and it’s like a nice shaped contrast with the green of the moss as a backdrop [below].
Margaret: Could we do it with non-native things too, if people have little tiny other things?
Uli: Absolutely.
Margaret: So this is kind of getting me thinking. I have a lot of mossy lawn [laughter]. Yeah.
Uli: One of my favorite really early, early bloomers is Iris reticulata. And there’s the species, and then there’s a couple of great selections. ‘Katharine Hodgkin’ is one with a really nice pale blue flower. These would just look absolutely stunning in a little moss patch. And then after the flowers are done, you get some foliage. And then at some point it goes dormant in the summer. And then before you know it, it’ll bring you joy again in early March, when it emerges.
Margaret: Yeah. I mean it really, again, as opposed to bemoaning a spot where this moss is happening or whatever, or as you say, having these tiny little treasures that are smothered under the deciduous forest canopy in some places, put them on this carpet and then they’re like little jewels. Yeah. Wonderful.
Uli: And if it’s like a wet spot, you could play around with little saxifrages or primroses. I mean, there’s all kinds of possibilities. If it’s a drier spot, there are woodland sedums, for example; Sedum ternatum, for example. I mean, there’s all kinds of possibilities that you could really explore. There’s a whole world of small, miniature plants. Maybe even some things borrowed from the alpine plant world would do really well in this kind of situation.
Margaret: Right. Well, Uli Lorimer, I’m so glad to speak to you and congratulations on 125 years of Native Plant Trust and the 10th anniversary of Trillium Week, which is coming up May 11th to 18th. And like I said earlier, I’m going to give all the links for how people can attend your virtual symposium on Saturday, May 3, for instance, at which you’re one of the speakers, or come and visit in person. But it’s good to speak to you and think about spring, because it’s been a little bit of an up-and-down spring in the Northeast where we both are [laughter].
Uli: No, I’m glad it’s here and the sun is shining, and there’s all sorts of exciting things popping out of the ground right now.
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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 15th year in March 2024. 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 April 28, 2025 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).
