WITH THE EXPLOSION of interest in native plants in recent years, I know I’m not alone among gardeners who are scouring catalogs and specialty nurseries, looking for the right native to match every garden purpose, from trees on down to groundcovers. A new book by Uli Lorimer, director of horticulture at Native Plant Trust, has added some plants to my wishlist, including some native annuals. And it even has me pondering diversifying my lawn with some violets and hunting down a few more native vines and…oh my goodness.
Uli Lorimer, author of the just-published book “The Northeast Native Plant Primer” (affiliate link) 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, became director of horticulture at Native Plant Trust, America’s oldest plant conservation organization, which was founded in 1900 as New England Wildflower Society.
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Read along as you listen to the May 16, 2022 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).
native annuals with uli lorimer
Margaret Roach: Welcome back to the show, Uli. Must be beautiful at Garden in the Woods, and Nasami Farm and all your places there.
Uli Lorimer: Yes, spring is definitely happening and there’s so many things coming out of the ground now. I was just remarking that this is one of my most favorite times of year, as there’s that fresh green all over the carpet of the forest and little tinges of fresh green leaves coming in the leaves of the trees. And I always find it’s a time full of promise for the gardening season ahead.
Margaret: So you’ve been working with native plants since when? And did you ever imagine a moment like this where they’ve really finally become the “it” thing? You know what I mean, where they aren’t an alternative, where they are a mainstay more and more?
Uli: So my interest in native plants professionally goes back to my days at Wave Hill, actually. And I was their woodland gardener there, and probably spent more time pulling out invasives than planting natives. But it was the beginning of my formal interest in them. Wave Hill, of course, exposed me to a dizzying variety of other kinds of plants for which I have fond and great appreciation for.
But it feels very satisfying to be at this moment where the momentum that we’ve slowly been building over the last 10, 15 years has really gathered speed. And I think that the past couple of years particularly have really opened folks’ eyes to how important it is to include natives in their gardens.
Margaret: And do you think there are headline kind of reasons or current event reasons, or what’s the awareness that you think is mostly spurring that?
Uli: Well, not to say that good things came out of a global pandemic, but I do think that the circumstances forced a lot of people to stay home. And if you were fortunate enough to have a garden, to really take a hard look at it and say, “Hey, look, this is something really special.”
And then that coupled with this ever-growing drumbeat of bad news about climate change, the anxiety that people feel around what the future holds, along with the bad news about the loss of biodiversity. And whether you’re talking about birds or insects or pollinators, there’s lots of different ways that we’ve measured this. And then seemingly every week, there’s a new article talking about declines in some way.
So I think all of this adds up to people really wanting to do something to support the environment, to do what they think is right, and turning to the plants that are in their backyards and in their local parks seems like a logical choice.
Margaret: Right. So the book, which is very timely for the reasons you’re just talking about, is arranged by plant groups. So there’s 235 different plants, from trees and down to grasses and sedges and rushes, and in between wildflowers and shrubs and ferns. Actually, ferns are one of our common favorites and we’ve talked about that before on the show.
I especially loved a section that was in and on native vines, which frankly I hadn’t even thought about. Except it turned out I had a bunch of them here in the garden [laughter] and I never really thought of them quite the same way until I read the chapter in the book.
But there’s also a section on annuals, which off the top of my head I probably couldn’t have named any native annuals. Do you know what I mean? We think annual—zinnia, marigold—you know?
Uli: Yeah. I mean, I think the book provided a unique opportunity to expose people to the fact that we actually have real true native annuals here. And I think that for many gardeners, when we think of annuals, we’re actually really thinking about plants that are not cold-hardy here.
These things are all… They may be perennials in warmer climates, but we plant them for summer color and as bedding annuals, with the understanding that they’ll turn to mush as soon as we get a hard frost. And that’s an important distinction, because true annuals are part of nearly every flora. And these plants have evolved to germinate quickly to cover ground, to flower freely and early, and to make as much seed as possible, because that’s how they return the following year.
And so I find them as a really useful group of plants in gardens because, for those very reasons, they fill in around tough spaces. But you can’t think of them or conceive of them as long-term members of any kind of design. They’re here for a short period of time. They move around. And sometimes they pop up in just the perfect place. And then sometimes it may be not the perfect place [laughter]. And so they’re easy if you need… And it brings an uncertain degree of serendipity to the garden; I think is really lovely.
Margaret: Yeah. Well, I mean, I think there are, I don’t know, seven or so in the book. And I realized I only had two of them here, and I didn’t even know most of the rest of them. I think one other one I knew and the rest I’d never even heard of. So the ones I knew were herb Robert, I think that’s Geranium robertianum, is that right?
Uli: That’s correct.
Margaret: And over the years, I’ve read about that, questioning whether it’s native or was introduced a zillion years ago, or where it’s from. And I’ve never really gotten a clear picture. But I guess you’ve done some more homework?
Uli: Well, as I understand it, it’s one of these what we call circumboreal plants, with really broad distributions in the Northern Hemisphere. And you can find them in Siberia, as much as you can in Europe, and in Canada and North America as well. And yeah, I mean, for dry shade situations, it’s a great plant.
Margaret: Beautiful leaves. I love the leaves.
Uli: Yeah, the leaves are great. Some people, the flowers, if you crush them, it has kind of a cilantro-like fragrance to it, which I’ve always found pretty pleasant. I know some folks don’t like the smell of cilantro. But it for me is one of those things when I have to edit it out, I always enjoy the aromatic experience.
Margaret: Interesting. And the flowers are kind of a lavender-y color on herb Robert. But the other one I knew, and everyone probably knows, and actually at the moment I’m doing some editing because its very distinctive seedlings are just popping up through the surface here where I garden in the Hudson Valley of New York, is jewelweed.
Margaret: A native impatiens.
Margaret: Give us the pitch for jewelweed [below], because I think a lot of people just yank it all out, but…
Uli: Well, so it has tremendous wildlife value. I think it has just lots of wonderful little stories. The flowers are wonderful and complex-looking. They attract hummingbirds.
If you like cardinal flowers and trumpet vines to attract hummingbirds, they’ll come and spend lots of time around a jewelweed patch, just as much, because of that long nectar spur that wraps around in the back of the flower. It is a host plant for other things. And it likes damp places.
And if you have kids, there’s this really wonderful activity. One of the common names for jewelweed is touch-me-not, because the seeds are what are called explosively dehiscent. So if you touch them, they literally explode and eject the seeds out away from themselves. And so I find that’s just a wonderful activity with young children to get them engaged with dispersal and all these wonderful stories. To have them go through the patch and touch a seed pod and watch it spring to life, it’s just really fantastic.
One of the other things that I really like is, as a quick side note, sometimes in the spring you’ll find little seedlings of jewelweed tightly clustered together.
Margaret: And that’s what I was going to say, is it’s like a little bouquet coming up together, you know what I mean?
Margaret: It’s just so tight. And it’s just like, “What happened there? Who did that?”
Uli: So that is the activity of our delightful white-footed mice. And so the mice collect the seeds and stash them all in one place [laughter]. And then of course, they forget, or the plants germinate. And so whenever I see those tight little bouquets, I think about an industrious little mouse the season before, collecting the seeds in the ground and maybe eating a few and creating a little store for the winter. And it always brings a smile to my face when I see those little clumps there randomly distributed.
Margaret: It reminds me of another, someone was telling me… I was talking about trillium with someone, another one of your loves, recently. And she was saying sometimes out in the wild, she’ll see a perfect circle of trillium. And those were seeds deposited by an ant. So here are our animal partners doing the planting, right [laughter]?
Uli: Yeah. And I grew up with Beatrix Potter stories. And so this is the same kind of idea, that I can imagine an industrious little dormouse or white-footed mouse going about their lives and collecting seeds. And I think it just connects me to my childhood in a way.
Margaret: Really, right. So one that I don’t grow but is in the list of native annuals was Rudbeckia hirta [above], the black-eyed Susan. Now that’s something that people will conjure a mental image of pretty easily. So that’s an easy one to grow?
Uli: Yeah, it is. And there’s some conflicting information about whether it’s actually really an annual or a biennial, or even a short-lived perennial.
But it often gets used as a cover crop when people establish meadows, because it germinates quickly and it has these really big, showy flowers that are very attractive. The seeds later on, in the fall, are greedily gobbled up by songbirds and goldfinches. And again, if, once you learn to recognize the seedlings, you can either let them run free and have a beautiful display, or edit them out if you feel like. And it’s good for sunny areas, disturbed areas. They don’t want to grow in the same soil that your vegetables grow in. So if you’ve got gravelly soils or tough, poor soils, this is a great choice.
Margaret: Among those that I really didn’t know, I’d heard about partridge pea, but I’ve never seen it in person. I don’t even know the genus and species, but partridge pea, tell us about that?
Uli: Yeah. So partridge pea [Chamaecrista fasciculata] [above] is a bean family member. Again, it’s it more broadly distributed in the Midwest and prairie states, but does make its way into the East here. And we’ve got two species here. The one that I’ve listed, it has larger flowers. There’s another species called Chamaecrista nictitans, that has smaller flowers.
But they’re, again, true annuals. They germinate quickly. The pollinators absolutely go nuts for the flowers. We use this with, at Darrell Morrison‘s suggestion, as a cover crop when we established the meadow at Brooklyn Botanic Garden. The first year, it was all partridge pea and I was really worried because we had sown all these grass seeds and I didn’t see anything. And the shade that plant created was actually a nice little nursery for all of the grass seeds.
And within two or three years, the partridge pea was pushed to the edges, and became a little bit more sporadic. And that whole experience really helped me to understand how useful annuals are in garden design. And that, particularly if you’re doing new installations and you don’t want to worry about lots of weeds, things like partridge pea are great. And their seed pods are also explosively dehiscent.
Uli: Yes, like bean pods, they have little square seeds and they will split and twist like a propeller blade when they’re dry. And on really warm days in August, you can sit by your plants in the sunshine and hear this little popping noise as the seeds disperse. Just really, really wonderful, and sort of brings a little auditory experience into the garden.
Margaret: And it’s almost like a little bushy, shrubby creature with lots of yellow flowers up and down.
Uli: Yes. And again, in Brooklyn, we had a lot of visitors from Central America and places where the sensitive plant, mimosa plant, grows. And people used to think, “Hey, is this it?” And they would touch it expecting the leaflets to clasp together. So it has that same sort of delicate look to it, but it’s a really tough plant. And again, for anything that has poor soils, well-drained soils, and initially not a lot of competition, it’s a fantastic cover crop and a great pollinator plant.
Margaret: And one I’ve never heard of, I mean, I don’t know where you came up with these, Uli [laughter]. I mean, really it’s funny because sometimes, I mean, I may have never seen a plant or grown a plant, but a lot of times I will have come across it in literature or someone will have mentioned it in a slideshow or whatever. But oldfield toadflax, Nuttallanthus canadensis maybe [above]?
Uli: Yes, Nuttallanthus. So we have a number of native flax plants. They’re related to the European flaxes that are the source of linen as a textile. And so this plant similarly has the same sorts of fibers in the stem, but it’s very labor-intensive if you ever want to make any linen out of this. But it’s a really delightful early annual that I see all over the place on roadsides and highway, the little cloverleafs, the on and off ramps, just the little tinge of blue.
They’re just really wonderful little plants and they have a flower that’s very similar to a Lobelia, so good for early pollinators, and a favorite of our native bumblebees. And it makes a whole lot of seed. So really just need to introduce it once in your garden and you’ll probably get recruitment year after year after year. Again, it’s an unknown plant if you’re not a botanist, that I think could really use a lot more exposure in horticulture circles.
Margaret: And then the one that for me, in the annual chapter of the book, the prize for the—well, actually, maybe there were two, these last two—for the great common name is the blunt-leaved rabbit tobacco [laughter] [photo above].
Margaret: I don’t even know how to parse that.
Uli: Well, I mean, smoking aside-
Margaret: Smoking rabbits.
Uli: Who makes the…
Margaret: Common names?
Uli: The Latin name is also a huge mouthful [Pseudognaphalium obtusifolium]. So we use this plant also at Brooklyn Botanic Garden, as part of our cover crop mix. And it’s very similar to pearly everlasting or sweet everlasting. In fact, as a cut flour, it’s a good dry cut flower like those everlastings and strawflowers. It has this really wonderful aromatic foliage. As I said in the book, it’s reminiscent of maple syrup in a way.
And I remember very distinctly, in an encounter again at Brooklyn Botanic Garden, on a warm day in August, a man and his son came in. And the son turned to him and said, “Daddy, it smells like pancakes in here.” And they were like, “I’m hungry.” And it was this. They didn’t know where the smell was coming from. It was a combination of sweetfern, of Comptonia, and this rabbit tobacco, just commingling to suggest a nice warm pancake breakfast with syrup on top.
Margaret: Yeah, I think the last one in the annual group is forked bluecurls [Trichostemma dichotomum] [photo above], which again, is one I’ve never heard of, and has a purple-y blue flower, maybe?
Uli: Yeah. It’s a mint family member. And so, it has also really wonderful aromatic foliage that is pleasant when you crush it. And then the styles of the flower are a big curl, a big round curl, almost like an eyelash. Which is why it gets its name. And again, pollinators, particularly our smaller solitary-nesting pollinators, absolutely love this plant and will readily visit it.
And as you can see, the image in the book shows that it’s quite floriferous, the flowers will drop but new ones will come. And it’s a great one for pathway edges, for rocky slopes and sandy soils. There were other annuals that I had wanted to include in here, too. I think overall, one of the hardest parts about writing this book was limiting it to 235 plants.
Margaret: Of course, of course. Yeah. Well, and as I said in the introduction, I mean, you have other sections. I mean, for instance, in among the wildflowers or the perennials or whatever, you show a couple of different kinds of violets. And it made me think, it made me remember, people are constantly ripping out violets, which are not an annual, which are so important. And I thought, yes, I have to really be happy that I have so many. And I think you even suggest maybe, or you’ve suggested to me in the past, that we could even encourage them in our lawns and so forth, and diversify the damn grass, right?
Uli: Yeah, absolutely. I think the violets are a perfect addition to any sort of lawn planting. They grow relatively low, so they don’t mind if you mow over them occasionally. And if you do let your lawns go a little bit longer, particularly in the springtime, you’ll get a wonderful show of either dark purples or blues or white colors. And it’s an important resource for early emerging pollinators. They’re a wonderful diverse group. And again, if you feel like there’s too many, then you edit some out.
Margaret: Right, right.
Uli: They fill in around all of these wonderful tough spots. They pair well with stronger-growing, clump-forming ferns and other sorts of woodland perennials. And I just find them really delightful and cheery.
Margaret: Yeah. I just wanted to shout out one of the things in the vine chapter. Because I knew some of them—and I have some of them, the perennial kind of vines, Dutchman’s pipe and the wild yam, Dioscorea, the trumpet honeysuckle, I have those in the garden, Lonicera sempervirens. But that crazy wild cucumber.
Uli: Oh, yes.
Margaret: I thought that was a weed. So, Echinocystis lobata. Just quickly tell us about that, because is that an annual?
Uli: It is an annual. It’s another annual vine that, again, likes the edges of wetlands and hedgerows and anywhere where it can have good, consistent moisture. The foliage is very attractive. It’s a cucumber relative, so it has that almost star-shaped leaf. And then it makes actually two different separate male and female flowers, and they’re wonderfully fragrant.
I see this commingling with the Clematis virginiana often. My friend Dan Jaffe Wilder grows this on a fence line at Norcross Wildlife Sanctuary. And it’s just a wonderful… You can train it to go up really anything that it can ramble onto. And I think it’s just, again, another great member of our flora that most people don’t know about.
Margaret: Well, and again, I thought it was a weed. Do you know what I mean? It’s so robust and it comes out of nowhere and then, whoosh, it covers entire shrubs. And you see it along the sides of the roads and stuff, in hedgerows. And you think, “Oh, that must be an invasive,” just because so much stuff there is.
Uli: And that kind of growth pattern where it germinates quickly and then grows very rigorously just to make more seed is exactly what annuals do.
Margaret: Right, right.
Uli: And it’s a plant that if you have a little bit more space to let it ramble, it’s certainly one that you can welcome in. If you have a smaller garden space, there are other choices that might be a little bit better.
Margaret: Well, Uli Lorimer, again, I say congratulations on “The Northeast Native Plant Primer,” and I’m always glad to speak to you. I’ll talk to you soon, O.K.?
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(Photos from “The Northeast Native Plant Primer” from Timber Press.)
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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 May 16, 2022 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).