defining ‘native’ and choosing the right native plants, with dan jaffe
WHAT MAKES a particular native plant a good choice for the home garden? And where can we look for clues into which natives will do best in our particular location and conditions? I asked advice from Dan Jaffe, who at the time of our 2018 interview was propagator and stock bed grower at New England Wild Flower Society, and author, in collaboration with his colleague Mark Richardson, of “Native Plants For New England Gardens.”
Wherever you garden, he has advice to help you think about what to look for in a garden-worthy native and more, and how to really define native, anyway. I learned the concept of ecoregions—about choosing plants not because I live within a particular county line on a manmade map, but instead guided by larger forces of geology and natural habitat.
Read along as you listen to the July 23, 2018 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here). Plus: Enter to win a copy of the new book, by commenting at the bottom of the page.
selecting garden-worthy native plants, with dan jaffe
Q. I haven’t been to Garden in the Woods in too long, and I’m going to come visit you soon, I promise. [Laughter.]
A. We’d love to have you, and anyone’s welcome here. This place is pretty cool right now. We’re a very seasonal garden, and I’d say the Woodland Garden really shines in spring, but right now, the meadow is incredible.
Q. I bet. So your headquarters kind of is Garden in the Woods in Framingham, Massachusetts?
A. That’s correct. The headquarters of New England Wild Flower Society [which was renamed Native Plant Trust in 2019] is Garden in the Woods. It’s a 45-acre botanical garden. You know, we’ve got classroom space, we’ve got the garden itself. We sell plants here. Our conservation offices are here.
Q. And briefly, you then at New England Wild Flower Society, you propagate plants and other things, and you teach I think as well, don’t you?
A. Yes. We’re, you know, we’re a kind of classic small organization, so we all wear a lot of hats. I’m what’s called a propagator and stock bed grower, which pretty much means … Well, the majority of our propagation work is done out in Nasami Farm. It’s our propagation facility. And think about your kind of standard propagation facility—you know, greenhouses, plants and pots, the usual routine. They probably do a good 95 percent of the propagation work that we do.
What I do is I work in our in-ground nursery at Garden in the Woods, and I focus on either things that don’t grow very well in pots, or a lot of experimental species that we’re not sure if we want to be growing or what we might do with them or what they can handle as far as kind of cultivation settings. It’s a lot of kind of R & D sort of work.
And then I also teach a lot of classes, give a lot of lectures, take a lot of pictures. We all do a little bit of everything here.
Q. Yes. What I love about the new book, “Native Plants for New England Gardens” that you did with Mark Richardson [above right]: In the beginning, in the introductory area, it sort of talks a little bit about what native means to you, as professionals in this field. And it has sort of special emphasis on the ways to look for guidance, from maps—and I’m a range-map person, I love all the range maps, but they’re never quite exactly the same from source to source. So tell me, what is a native plant? [Laughter.]
A. Geez, how long is this show? We need a couple of hours here.
Q. Two years.
A. You know, I think that a real good, honest definition is that it’s a definition that has been changing as the research has advanced. In the past New England Wild Flower Society kind of focused on native to North America. And at the time, that made a lot of sense for us. And now as we’ve gone forward and other native plant organizations have come about, that’s not necessary anymore. And so we started focusing on New England.
But we realized quite a bit recently that plants don’t really care about political lines. The idea to native to Massachusetts or native to Connecticut or native to a county is just … You know, a plant doesn’t care about those things. It cares about things like rainfall patterns and underlying bedrock and soil geology and all these other factors that kind of came together to make the ecoregions.
Then this scientist named Omernik kind of created these ecoregions that are kind of these broader kind of zones. And they’re set up in different levels where you can get really, really specific to really, really broad. You know, Level I ecoregions is pretty almost continent-sized. And then it gets down to a Level IV I believe is the most advanced, if I’m remembering that right.
And so these are allowing you to take a look at the nativity of a plant based on these sort of climatic and ecological zones. And it makes a lot more sense for plants. And what’s kind of cool is when you start looking at the range of plants, you find that a number of them really match these ecoregions very, very well.
And then if you, say, look at the range of maybe a specialists pollinator of this plant whose caterpillar eats the plants, you’ll find, wow, the pollinator’s range matches the plant’s range, but really follows the ecoregions really closely, you know? The evidence is there to support why this might make sense.
Q. Right. Because even in speaking of like boundaries and so forth … So I’m in Columbia County, New York. And that’s sort of mid-Hudson Valley next to the Berkshires in Massachusetts, O.K. But even in my county, we have different elevations by nearly a couple of thousand feet, right?—we have alongside the Hudson River and we have adjacent to Massachusetts, hilly and rocky; mountainous. And we have a lot of different habitats, so to speak, or ecosystems—ecoregions, as you’re saying. So even within my little county, I bet it’s … You know what I mean? Something isn’t native to every single square foot, even of a county necessarily, correct?
A. Oh, of course. I mean, you’ve got, you know, different habitats from one site to the next. And just because something is native in say our ecoregion, doesn’t mean it’s the right plant for whatever place I’m currently staring at. You know, don’t put the dry-loving plants in the wetlands. It’s just not going to work, whether it’s native to the region or not.
I think a big part of it that we need to kind of think about is not just what do we mean by native, but why do we care and how much should we care? You know, do we want our plants to all be native right to our super-local site? Or are we O.K. with the broader definition of native?
And then there’s the question of, you know, are we going to go get mad at someone because they’ve got some tomatoes and some rosemary planted on their site that don’t happen to be natives?
A. I think sometimes we start kind of thinking on such a detailed scale that we kind of lose the bigger picture. And I think being realistic about these sort of concepts is important.
Personally, I come down on … I like a nice, tight, strong definition of native. But at the same time, I don’t think you necessarily need to have a 100 percent native landscape. Mostly because I don’t think that’s very realistic. As much as I’d love to support a landscape that is nothing but natives, to try and remove every non-native plant from the landscape is just an effort in futility.
Q. So these maps that we were sort of alluding to, these ecoregion maps, they’re from the EPA I think or something? Is that correct? Those are the ones you refer to in the beginning of the book, I think.
A. Yes. Those are definitely … Those are the ones.
Q. So I’m going to turn people on to that, because I didn’t know about those. I know about a lot of, you know, the BONAP maps and the whatever, NPIN [maps for Texas] or whatever—you know, the different organizational range maps. But I didn’t know about these. So this is kind of interesting to me. I mean, the different type of map.
A. Yes, they’re extremely useful maps. I mean, we look at … So we are a regional organization, so what we kind of call native as far as the book is concerned are these five ecoregions that are present in New England.
And that gives us kind of a nice broad like … Those are the plants that we’re picking from for, say, Garden in the Woods that we want to represent, we want to show off, we want to kind of teach people about. And in many cases, those are the plants that we are recommending with people who say, you know, “What should I be planting? What I should keep? What should I remove?” You know, that sort of stuff. That’s kind of the basis for it all.
Q. So, also in the intro, you talk about how plants have migrated. So, you know, if we want to talk about this not as a physical boundary like the State of New Jersey, the State of Connecticut, the State of Alabama, but as a point in time. Plants have changed over time. And I’m always fascinated when I give workshops in my garden and I’m pointing to things and people are saying, “What’s that? What’s that? What’s that?” And then I frequently will say where it’s from, or anything that I know about it.
And I find that I am pointing to a lot of things from the Southeast. Like, here is my Fothergilla. Here’s my Aesculus parviflora. Here’s my Oxydendrum, the sourwood tree. Here is my Callicarpa. Here is my, you know, Chionanthus, the fringe tree. And they’re from the Southeast. But maybe they weren’t always just from the Southeast, right? Plants migrate.
A. Oh, most definitely. Like one of the things we always say about defining native is you always need a qualifier. You can’t just say, you know, “native.” It’d be … To make a really stupid point, I could say the purple loosestrife is native to the planet Earth.
A. But that obviously is not a good enough reason to plant it in New England.
A. So you need a native to, and you need a native when. So, you know, the general idea for most in New England is we look at European settlement.
Q. As the point in time, right.
A. And there’s good reasons for that and kind of, you know, rough reasons for that. Yes, as the point in time.
On the good side of things, it kind of draws a nice stark line between plants that have been moved around by natural processes or by the native First peoples, versus plants that came across an ocean on a ship—the great difference there.
But the one big thing I don’t like about that is it kind of insinuates that evolution stopped the day Columbus hit this landscape, which obviously is not the truth. Plants do migrate. They do move. And there’s lots of plants that are not native here now, but were very likely native here in the past. There’s all sorts of cool gray zones.
There’s reason to believe a lot of plants are still moving north. In some cases doing it quite well, and in other cases having trouble because of the fragmentation on the landscape.
One of our favorite examples that always leads to one heck of a good discussion is black locust. You know, by the ecoregion definition, we can call that plant native to the New England ecoregions. And according to the State of Connecticut and I believe the State of Massachusetts, too, we could also argue that is an invasive species in New England.
A. And there seems to be some pollen data out there saying that this planet was likely native throughout New England before the glaciers came and pushed it all down. So it’s this wonderful gray zone that kind of shows us that we still have more to learn and we still have more to understand. And should we be defining plants as invasive on a state line? You know, we’re saying that it doesn’t make sense for native, why would it make sense for invasive? Instead, should we look at ecoregions for that as well?
But plants are most certainly migrating. And, you know, the kind of environment changes as plants move in and and move out of it, and I think that’s something to accept and work with.
Q. And you just said glaciers. And the ones that I was listing before … The Chionanthus, the Fothergilla, the Aesculus [above. flower detail with silver-spotted skipper], the Oxydendrum, etcetera … I mean, for all we know before the last Ice Age, their range may have been much farther north, right? I mean, and I don’t know the fossil history of those particularly. But, you know, I mean, once Peter Crane, ex-head of Kew told me that Ginkgo, one of his favorite plants, once was native in [North] Dakota, the fossil records show.
A. Oh, that is cool. I haven’t heard that.
Q. It’s super-cool, right? So you know what I mean?
A. Yes, it’s very likely that, if not all, at least many of the plants you just mentioned were indeed native here and then, you know, that time again comes into effect. If you want to be a real stickler and say, “I want plants that were native here, that have been native here,” if you go back far enough, nothing was native here except for ice and some cyanobacteria.
Q. Right, there you go. [Laughter.]
A. So maybe we should remove every plant on the landscape and call that native. I think we need to be realistic, and we need to kind of accept the fact that as soon as we have a definite definition, we’re going to have new research and new knowledge out there that’s going to force us to kind of keep educating and changing.
You know, science is a changing kind of passion. It’s something that will evolve as time does. And I think that’s something important to kind of connect to.
Q. Yes. So the title of the book is, you know, says dot, dot, dot … it’s native plants “for New England Gardens,” right? It’s not just native plants, like a field guide. So what qualities in a native do you look for to have it sort of make the list as garden-worthy?
A. Yes. I mean, we kind of had a little bit of discussion as to where to go with the book and where to go with the title. And it kind of fell into … It fell out very nicely. It just kind of naturally happened, where we decided what we really wanted to focus on is plants that people could work with and plant on their landscapes.
We’re not talking about restoring wild populations. We’re not talking about kind of what I talk of as like traditional conservation work. We’re talking about people planting plants in, to one extent or another, built landscapes. In many cases, home landscapes. But, you know, a place where we’re planting.
So we wanted plants first off that would work well in that case. You’ll notice there’s certain species like the trillium are not represented in the book. The lady’s slippers are not represented in the book. We didn’t want to pick plants that you really got to be a plant expert to succeed with. We want to first choose plants that people would succeed with. So these are good, hard-working, easy-growing to one extent or another kind of, you know, wide-ranging habitat needs as far as what they can handle.
We also wanted to do plants that were to some extent the tried-and-true species. You know, we didn’t want to have a native plant book without wild geranium Solomon’s seal in it. But we also wanted a chance to introduce people to species they may not already know about but could become tried-and-true species if more people got connected with them. Things like Monarda punctata, the spotted bee balm, or Euphorbia corollata, the flowering spurge, are species that I find most kind of typical gardeners have not heard of before. And these are wonderful plants that are not difficult to grow, don’t need specific environments, and really have a lot to offer. So that definitely came into it as well.
]And other than that it was pollinators—and we had a thing for edibles. We wanted beautiful plants. There’s this weird kind of concept out there that native plants aren’t pretty. And it’s completely false.
I mean, the funny thing is people will tell me, “Oh, native plants aren’t pretty. But I really like my bee balm.” And I’ll tell them, “Well, you know, bee balm’s a native plant.” And all of a sudden you see the light bulb go off. But we wanted to make sure that these are plants that you’d want to put in your garden.
Q. I smiled because you put in some plants that when I mention them and I recommend them to people, again at workshops and stuff like that, you know, I’ll say, “Look. You can really improve the sort of habitat aspect of your garden if all you did was plant winterberry hollies along the perimeter. You know, give me back 8 feet along the perimeter of your property and some native viburnums and some winterberry hollies, and carpet it with Parthenocissus, with, you know, Virginia creeper.
And they look at me and they’re like, “That’s a horrible plant. That’s a terrible plant.” [Below, Virginia creeper.]
Q. And I say, “Let wild grape grow on your fence and that will help things.” “No, no, that’s a horrible plant.” [Laughter.] You know? And you include those in the book, so I was vindicated.
A. The amount of times I’ve had to argue with people when they tell me goldenrods are invasive and I need to explain what invasive means, what native means, and then … I think the big part in plants like that is really about site choices.
You know, one of the things I’m really always pushing for is no place can’t be planted. And, I mean, gardens are one thing. I’m not going to recommend planting, you know, the Canada goldenrod in the middle of your delicate little garden. But if I’m going to start talking about planting highway medians and parking lot islands and abandoned lots, that is not the site to put a delicate little Hepatica. That is the site where I want a plant that can handle being run over by an 18-wheeler, abused up the wazoo. Heavy amounts of salt pollution, all that. Like, we need native plants that can take those environments.
And I will take, you know, roadsides covered in vibrant yellow goldenrods any day over roadsides with Kentucky bluegrass. So it’s really a matter of siting. I mean, one of our favorite plants are wild strawberries, which we’ve kind of recommended as a really good lawn alternative. And we’ve been working with them in garden settings. But they’re a vigorous spreader, so it’s really a matter of good siting. Planting it in amongst your trillium and your lady’s slippers and hepaticas is probably not a good idea, unless you really like wild strawberries and want to get rid of all of those.
But if you had, say, what you were describing—winterberries and, you know, witch hazels and spicebush, and native azaleas and just a good shrub layer, and you want something to just cover the ground underneath, yes. Wild strawberries, Virginia creeper, the Vitis labrusca, the fox grape, you know? The wild strawberry’s not going to out-compete the witch hazel. So it’s a matter of correct siting and choosing where to put these plants that really do kind of push on you.
Q. I wanted to ask about some other specific plants. You’re mentioning some favorites and I’m obsessed with the genus Aralia. And maybe 20-plus years ago, a native plant person from the New York Botanical Garden at the time, she gave me a couple of little seedlings of Aralia racemosa [above]. I don’t even know what it’s called, American spikenard or something—I don’t even know if it has a generic name, does it, a common name?
A. It does. I’ve heard spikenard. I’ve heard American spikenard. And I’ve been looking for the reason behind this, but in a number of sources I’ve seen it listed as “Life of Man.” And it’s such an epic-sounding common name I feel like-
Q. It’s an epic plant.
A. …there’s got to be a good story behind it. But I’ve never found the story.
Q. And that’s a plant I love, and I’ve grown it for more than 20 years. Now, this is a perennial to beat all perennials. This is a big perennial. Dies to the ground, it’s herbaceous, every winter, but whoa, right? It’s a big thing. Tell us about it.
A. Oh, yes. I mean, it almost looks like a hobblebush when it’s in, you know, kind of its full glory. I mean, when I see it in the wild, sometimes 18, 24 inches. Oftentimes more. And when you bring it into cultivation, it’ll easily do 5 or 6 feet tall. Big, broad compound leaves, wonderful structure to it. A flower that if … They’re starting to bloom right now. The flower isn’t super-showy, but the berry display that follows-
Q. Wow, yes.
A. …is phenomenal.
A. And quite tasty at that. It’s really excellent muddled into gin and tonics. I highly recommend it.
Q. [Laughter.] You heard it here first, folks. Another plant that’s become sort of an “it plant” for gardeners, you know, in many regions and albeit often a colorful leaf cultivar version of it for it’s ornamentality is Physocarpus. And Physocarpus opulifolius is in your book as well. Tell us a little bit about that as a shrub.
A. Right, that’s ninebark. And so we’ve been going back and forth a long time on how native is a native cultivar? Should we be recommending cultivars and so forth? And I find with Physocarpus, almost always people are talking about ‘Coppertina’ [above] or ‘Diabolo’ or these various kind of red-leaf forms. At one point we were thinking we really ought to start to just really only recommending the natural species.
And then at one point we were having this just kind of brainstorming discussion and we said: Listen, we were talking about invasive species, and talking about replacing invasives with good natives. And in the case of something like burning bush, it’s like which one of the 30 fabulous fall-color plants do you want to recommend in its place? We eventually got to Japanese barberry, and realized that what people really like about barberry is the color of the leaf, you know?
A. It’s almost always a red-leaf cultivar, and that’s what people want. And it kind of led us to that kind of light bulb went off and we said, you know what? I will take a red-leaf Physocarpus, which might not have as much value on the landscape as a natural species, but I’ll take that red-leaf Physocarpus any day of the week over a Japanese barberry.
Q. Good point.
A. Cultivar or not. And it kind of helped us to really decide how we wanted to tackle the idea of nativars and native cultivars and things like ‘Diabolo’ ninebark, which is one you can now find at our shop. It’s a great replacement for Japanese barberry. And if you’re looking for a good red-leaf plant on the landscape, I’ll take a red-leaf native any day over a non-native. It’s a tough shrub; it can handle really difficult conditions and really can look quite nice.
Q. Yes. Mine’s been cut back I think to the ground three times in its lifetime with me, as has ‘Dart’s Gold,’ the big gold one. That’s the other thing: If they get too big, out of shape, out of scale, you can cut them all the way, and I guarantee they’ll grow back again. [Laughter.]
A. Oh, yes. I love a plant that you can beat it and it comes back for more.
Q. Exactly. Another genus that I feel like I never heard about until recent years and suddenly it also has become sort of an “it” thing is Pycnanthemum, the mountain mints. There’s a number of those in the book.
A. Yes, and you’re right to say the genus that we haven’t heard about. Because I think there are six native New England species. Every single one of them is quite nice. There’s probably three or four that I think are really the most garden-worthy. And kind of you name the environment and there’s a mountain mint to kind of match the site.
For the moist areas, hands-down my favorite is Pycnanthemum muticum, the broadleaf mountain mint [above left]. It’s got a flower that is not very showy. But it shows off quite a bit by producing these big large silvery bracts that bring the pollinators in from a distance, where they’re then able to find that little pink flower.
So though the flower may not be showy, the plant most certainly is. And it’s a really, really valuable kind of source for … The amount of bee life that I see on one of these is phenomenal. I mean, you sit there with a camera and take 20 pictures and you’ve got 20 different species of cuckoo bees and mining bees and syrphid flies and various different digger wasps and all these different kind of life forms just coming in. It works quite nicely.
As far as dry sites are concerned, this is where it gets tougher, because there’s three or four good dry species. I think my personal favorite is Pycnanthemum tenuifolium [above right], the narrow-leaf mountain mint. I really like the texture on that one. It’s got a very thin leaf—not quite pine needle thin, but maybe rosemary leaf thin. A much showier flower and a smaller bract. So as showy as the broadleaf, but in a different sort of way. And it tolerates, you know, just sunny, sandy, dry, very, very difficult conditions. It’s one the few plants that I think really thrives in hell strips and, you know, kind of overly sandy sites. A great species. There’s a lot of good mountain mints.
Q. So we just have a couple of minutes left and I’m going to have to invite you back for another discussion, because obviously I have a million other questions to ask you. But everyone wants milkweed. So just a quick like 101. Everyone wants milkweeds, but they can be a little hard to manage. They can be tough guys. Any tips or whatever, anything that you want to tell us about … I have Asclepias syriaca, the one with the lavender sort of pinkish hanging flowers [above left]?
A. Yes. I think the 101 on milkweed is pick the right species for your spot. Kind of the same way we were talking about, you know, fox grape or Virginia creeper, Asclepias syriaca, the common milkweed, the meadow milkweed, is a spreader. It spreads rhizomatically, it spreads via seed. When you walk into a field and you see 30,000 milkweeds, you’re likely looking at syriaca.
And it’s great for fields, meadows, high-competition areas, sites that have been invaded. This is a plant that I think should line every sunny roadside in New England. And it’s not a great choice for small garden spaces, where you might want a tight, clumping species. In that case, I would go for either Asclepias incarnata or Asclepias tuberosa [orange flowers above right].
So incarnata‘s the one that’s sometimes called swamp milkweed. I like rose milkweed, a pink-flowering plant will grow in just average old garden soils and will also handle a very wet spot. Wonderful fragrance to the flowers. Can look quite a bit like syriaca at first, but it has a bit of a tighter flower to it, and it’s a clumping species; it barely seeds around. I wish it would more. And it doesn’t spread rhizomatically. It just kind of sits there and grows bigger each year.
And Asclepias tuberosa might be my favorite species, a little bit shorter than the others, with vibrant orange flowers. Will also grow in those average garden soils and in an average garden soil you can put incarnata and tuberosa right next to each other. But this one will also grow right next to that narrow-leaf mountain mint in those super-sunny, dry, sandy sites as well. It’s a coastal sandplains species, usually.
So it’s really a matter of picking which species you want to put where. I wouldn’t recommend syriaca for small spaces. Yet, I would not recommend tuberosa for, you know, invaded sites or roadsides.
more from native plant trust
- The organization’s website
- The Society’s “GoBotany” searchable plant database
- Garden in the Woods
- Nasami Farm
enter to win the book
I’LL BUY A COPY of “Native Plants for New England Gardens” for one lucky reader. All you have to do to enter is comment in the box at the very bottom of the page, answering this question:
What region are you in, and what are some of the native plants you especially rely on in your garden? (I love seeing all the insect and other wildlife action in my meadow of little bluestem grass and goldenrods and asters, and around a lot of native shrubs: winterberry hollies, viburnums, Aronia and blueberry, for instance.)
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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its ninth year in March 2018. 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 July 23, 2018 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).
(All photos except Aesculus flower detail from New England Wild Flower Society, used with permission.)