GARDENERS INCLUDING myself want to add more, more, more native plants to their landscapes to support pollinators and birds and other native wildlife, but what if our beds and borders are already established? Do we have to erase them and start over? Making room for habitat-style planting, even in an established garden that includes many “collector plants” from other parts of the world, was the topic with my friend, garden writer and photographer Ken Druse, along to help.

Figuring out which plants are native locally is one key first step, and at the bottom of the transcript is a list of some places to help you start in that search, no matter where you garden (including how to find your state’s list, and then your county’s from there). Up top, those are native Trillium erectum and Geranium maculatum in a shady bed at Ken’s.

Speaking of native plants, we also tackled a listener question about pruning Magnolia grandiflora—the evergreen Southern magnolia.  And on the subject of collector plants, Ken confesses to his latest acquisition—probably the most expensive single bulb he ever bought.

Ken Druse needs no introduction, but I’ll offer one anyhow. He’s a prolific author a with hit books like “Making More Plants” and “The New Shade Garden,” and “Natural Companions” (affiliate links). In 2019, he published his 20th, “The Scentual Garden,” about fragrance. Plus, he makes me laugh, which is very important.

Read along as you listen to the February 24, 2020 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Spotify or Stitcher (and browse my archive of podcasts here).

making room for natives, with ken druse

Margaret: How are you over there in your established garden, Ken?

Ken: Oh, excuse me, I’ve got a shoehorn over here trying to get a few native plants in, and-

Margaret: [Laughter.] I know; oh my goodness, oh my goodness.

Ken: I’m pretty good Margaret.

Margaret: Before we get started on the making room for more natives subject, actually an Urgent Garden Question arrived the other day from a listener/reader related to native plants, about pruning Southern magnolias. And I wanted to just throw it out to you, because I think you’ve probably grown Magnolia virginiana [note: Margaret misspoke; she meant Magnolia grandiflora], and in my colder, windier site, since they are evergreen, they wouldn’t be so good, so I just wanted to read to you Bonnie’s question and see if I could get your 2 cents?

Ken: Oh I have a question for you: Do you mean grandiflora, Magnolia grandiflora?

Margaret: I’m sorry, yes.

Ken: Both of those are interesting-

Margaret: It’s ‘Edith Bogue,’ ‘Edith Bogue.’

Ken: Right, grandiflora–

Margaret: Sorry.

Ken: … Magnolia grandiflora.

Margaret: Yeah, so ‘Edith Bogue,’ she says—Bonnie is the reader, and she says, “I want to know if you should prune and ‘Edith Bogue’ magnolia. Mine is about eight to nine years old, and it’s getting rather bushy and is more of a bush than a tree.” She wants to know what she can do about that.

Ken: Well, it’s a kind of a bushy plant naturally-

Margaret: It is.

Ken: … I grow a few by the road as a screen, and they’re fantastic, and they’re totally evergreen in my Zone 6A garden, but they’re shrubby, they grow more like Christmas trees than lollipops. And I just make mine a little bit tidier every year, just prune them a bit, but one could prune it into a lollipop, or enjoy it as a fat plant that you can’t see the road through.

Margaret: I think though, at eight to nine years, I mean it wants to be pyramidal, is that word, pyramidal? I never know how to pronounce that. The accent should be on which syl-LAB-le, right, is that the question? [Laughter.] So, you know, it’s bushier at the bottom and then narrower at the top, and that’s its natural habit-

Ken: It doesn’t lose its bottom branches, which is great.

Margaret: Right. So, if it were a young plant in the field at the wholesale nursery when it was a baby, and it was getting trained, that would to me be the time maybe more to shape it a little, do you know what I mean? Not eight or nine years after she’s had it, which means it’s probably 15 years, or whatever, you know, 12, 13 years after it got its early training, whatever that was.

Ken: Well once they get going, they’re pretty fast. I think eight or nine, that’s probably a pretty big plant.

Margaret: That’s what I mean. So, yes, I would never cut part way into a branch of one of these would you, I mean I would take out a branch-

Ken: No, I think you could shape it actually-

Margaret: Oh, you could?

Ken: Yeah.

Margaret: Huh. Yeah, I guess I think of them as … again, they have such a distinctive shape, you know, form.

Ken: Well, ‘Edith Bogue’ is kind of chubby, and also depending on the light, because in the shade, they’re gangly kind of, but they’ll do O.K. But as you said in the field, when it’s trimmed, it probably is a Christmas tree shape pretty much, or something like that. But in a garden and with little shade, and depending on the moisture and everything, mine gets kind of out of shape, and I do just prune back, I’ll prune back halfway on a branch if it’s sticking out in the wrong direction, and it looks like it’s misshapen.

Margaret: Oh, so you’ll go back part of the way into one of them.

Ken: Mm-hmm.

Margaret: O.K. All right, good. So the reason I bring that question in, even though we’re going to kind of digress slightly is that, that magnolia, as I’ve been corrected, grandiflora, which is what I meant to say, not virginiana, another native magnolia species, right? [Laughter.] Those are “native”, but they’re not native where you garden, or where I garden. And so we want to add more natives to our landscapes and so forth, and when you and I began gardening, most of the sort of “it” plants, and really I think it’s still true in many cases, were Asian plants, plants of Asian origin, yes?

Ken: Mostly, well they were aliens.

Margaret: Yeah-

Ken: Or exotics, because some came from Europe, too, but let’s say, that was sort of the trendy thing was for Asian plants, because for example, Japan and a lot of China has a very similar climate to ours and a lot of those plants-

Margaret: To the Eastern U.S., yes.

Ken: Plants from Japan have been around since like the 1850s or ’60s, but China was all new.

Margaret: Yes, so you and I both began, we got the bug, and we began as sort of collectors of cool things from oddball catalogs before the internet, not that we’re old or anything, and in fact, you even did a book called “The Collector’s Garden” in 1996, but two years before that, you already had an inkling about natives sort of before its time has come in a big way, and you wrote a book called “The Natural Habitat Garden” in 1994, and so here we-

Ken: With you.

Margaret: … yeah, well, yeah and you were kind enough to take me to all these incredible places where people who, again, were ahead of the curve were gardening with natives. But, here we are [laughter], we still kept collecting things, and what are we doing—what’s the remedy if we want to be more ecological, environmental, etc.? I mean, I’m not throwing out my whole garden—that’s the punchline for me—but I’m trying to come up with ways to make room, and I think you are too, yes?

Ken: And encourage people to think about this in the future. I think that if I could have an all-native garden, I would. But I can’t, and it’s not just because of the wonderful plants I planted over the years, although it has a lot to do with that, but well, some of them are so wonderful. So like you said, I’m not going to plow them all under, some of them are gigantic trees.

But you know, one thing I did is I took a survey of the plants that are here that are actually indigenous to my county, in the northwest corner of New Jersey-

Margaret: Wow.

Ken: … and I found that there were over 100 species.

Margaret: In your garden.

Ken: And they’re planted like, you know, there’s a phlox in with the other plants—there are so many. And you probably remember, I have a woodland garden that I made from the start 20 years ago with mostly plants from a 10-mile radius of this site, or where I live, but it’s a very complex site because it’s an island in a river and a hardwood forest, so there’s a lot to choose from. But there is a lot to choose from, and there are many, many places online, you were talking about online, where you can find lists of the plants that are indigenous or native to your area. [Garden phlox, above, in a mixed border at Ken’s.]

Margaret: Right, and with the transcript of the show, I can give at least a starter list of some of those. I felt really lucky, I don’t know how many years ago, within the last five or so years, there’s kind of an ecology project, a non-profit near me that actually for years has been doing … I’m in Columbia County, New York, and they’ve been doing the flora, the plant diversity, of Columbia County, and they’ve been surveying and keeping records and so forth. And so now where did you find yours, how did you do that? You just did a search for your County or-

Ken: On [a search for] “native plants of New Jersey,” and then I went to the New Jersey natives and the wild plants—it’s not wild, sorry, it’s the native plant site and then it had counties, and I clicked on my county, and up came this Excel sheet with hundreds of plants, and it was great.

So I just looked at the ones on the list that I already am growing, and then I checked some of them against the USDA map, just to check, another good site to check out, and I was surprised. And I’m not talking about nativars, is that what they’re called?

Margaret: Yes, cultivars of native plants. That was one of the big heartbreaks for me as I’ve learned more over the years, because when you and I, I remember distinctly, when I worked with you on “The Natural Habitat Garden” in the early ’90s, and we went to visit places, and I remember going to Mt. Cuba Center, which I think then was called Mt. Cuba Center for the Study of the Piedmont Plants, it’s in-

Ken: Yeah, Piedmont Flora-

Margaret: … Piedmont Flora, thank you, and it’s in Delaware, yes-

Ken: Mm-hmm.

Margaret: ... and we went to see the great plant person, Dick Lighty, who was directing it then. And he was showing us cultivars, or better forms of native plants that they were working on and then introducing, like a white trillium that reproduced more easily so that you could have more of them and they weren’t a million dollars—because in those days, trilliums were barely in the market, right? Unless they’d been stolen from the wild, right?

Ken: Yep, of course.

Margaret: Right. So he was showing us his various developments. And I can remember all the way back to then, and of course I adopted some of the plants that I learned about that day, and subsequently from his work and others like him. And some had variegated leaves [like the dogwood Cornus sericea ‘Silver and Gold,’ above], or had purple leaves or whatever, not the plain green, and I was devastated over recent years to learn that some of those aren’t as attractive to the native insects or whatever who have evolved alongside them [alongside the original straight species the nativar was derived from], they’re not tasty, they’re not nutritious to them, they aren’t a good host plant or whatever.

Ken: They also might be more vigorous than the actual natives-

Margaret: Yes.

Ken: … and push out the actual natives, and as you always used to say, only one plant can live in one place at one time.

Margaret: Did I used to say that? [Laughter.]

Ken: Yeah.

Margaret: Yeah, I mean double flowers for instance, and that’s another one, you know, we-

Ken: Oh well, yeah, right.

Margaret: … because they don’t have the nutritious value to these insects the same as the single flowers, that nature might have made, so it looks prettier in the garden maybe, but-

Ken: And it might attract insects, too, but they don’t get a reward, they don’t get-

Margaret: Correct.

Ken: … well, like a double rose, there isn’t any pollen.

Margaret: Right, so the nectar and the pollen resources would be diminished or absent or whatever, so, right.

• More: Doug Tallamy, on How Effective Are Nativars?

Margaret: So, these have been the harder more recent lessons for me. I guess the best thing that I did, and I don’t really even now why I did it, I don’t remember where I first met this plant, and I don’t know if you grow it, but winterberry hollies, do you grow winterberry hollies [Ilex verticillata]?

Ken: I do, but they look terrible, I think it’s because I’m not acidic enough.

Margaret: Oh, interesting. Maybe it’s because a nursery, a woody plant nursery near me has, along the road—it’s a rural place, and it’s a big property—and along the road for cutting, for the wintertime, they sell Christmas trees and then they have a lot of winterberries. And maybe because I always drove by them and I saw them at that time of year, and they were so fabulous, I don’t know, maybe that’s why I ended up with them, but right in the-

Ken: They’re wonderful.

Margaret: … right in the very beginning … but I don’t remember, you know, they don’t look showy, when you go to the garden center in spring, winterberry holly doesn’t look like the sexiest thing in the store, do you know what I mean?

Ken: Sure.

Margaret: It’s a bunch of twigs. [Laughter.] But I ended up planting maybe 40 or 50 of them around the place-

Ken: Whoa.

Margaret: … and so now, thankfully, I think I’m known to the birds of the area after 30 something years, it’s like I’m a favorite pit stop or something, and so those are real workhorse plants, those do a really good job of feeding a lot of native animals, especially birds, and the pollinators like them when they’re flowering in the spring. So that was one thing I did right, but then one thing I didn’t, I’m going to put it in quotes, O.K., “wrong,” was that of course I loved the variegated leaf, or the purple leaf, you know, I liked that cultivar/nativar form.

Ken: The golden berries.

Margaret: Yes. All right, so we’ve been thinking about this for a long time, but what are we going to do now, like how are we making room, like what are some of your tactics and so forth?

Ken: Well you know, I was talking about woodland bed that isn’t very big, but if you have a spot on your property, you can make a little Guilt Garden, how about that? We’ll call it a Guilt Garden where you have a bed, and you try to find out what the plants are that would fit that site, and are not only indigenous, or certainly not just native to the U.S., but local plants. And then try to acquire them responsibly, go to a native plant sale from the local native botanical garden or something like that, almost all of them have annual sales, or take a trip sounds good.

Margaret: Yes.

Ken: And then you can make a bed that’s specifically that, and add native plants in with your other plantings. I grow so much Phlox paniculata, and some of them are species because they revert to species form, but you can grow Phlox paniculata as part of your flower border, and that may be native; that’s native for me.

Margaret: Right, the tall phlox, the summertime, July, kind of August, yeah-

Ken: Right, like the garden phlox.

Margaret: ... garden phlox.

Ken: And they’re wonderfully fragrant, too.

Margaret: Now, Mt. Cuba a couple of years ago, we were talking about, Mt. Cuba Center, they do have a trials garden about native plants, and they trial alongside one another hundreds of varieties—I mean it depends on how many there are, but in the case of Phlox, a lot of different varieties of Phlox. And they published a great report, it’s available online, and it tells you which ones are the most insect-friendly of all the garden phlox, you know?

Margaret: And it’s amazing, by making the flowers bigger, which again, breeders did selecting for the larger flowers for garden appeal, didn’t necessarily make them better. And in fact, the one that’s J-e-a-n-a, and I think you pronounce it Jeana, but I don’t know, Phlox ‘Jeana’ [above, photo from Mt. Cuba] has the smallest flowers, they’re purplish, pale purple lavender-y colored, and it’s the most attractive by far to insects, to pollinators and the most effective for them getting fed. So it’s interesting, it’s sort of counterintuitive, you know, small is sometimes better.

Ken: I just ordered that plant from Select Seeds.

Margaret: Oh you did?

Ken: Mm-hmm.

Margaret: Oh, good, well you did a good thing.

• More: The Phlox Trial results, from Mt. Cuba to read on their website or as a downloadable pdf

Ken: Let’s make a list of some things to do, if we can.

Margaret: [Laughter.]

Ken: So never bring in a potentially invasive plant… and that can even be a native plant, there’s an Anemone canadense here that is one of the worst weeds I’ve ever had, but it’s a local plant and it’s actually threatened in Massachusetts. Plant oaks, local oaks, and you can tell why in a second, and if you’ve got some good plants on your property, leave them, encourage them, so how’s that for a short list?

Margaret: That’s a short list. But in terms of invasiveness, you said don’t bring in any invasive plants, and we’re going to try to eliminate some of the ones, I mean I’m on a lifetime war against Oriental bittersweet, for instance. [Below, 5 minute’s worth of weeded-out bittersweet seedlings from beneath shrubs in Margaret’s garden.]

Ken: But you didn’t plant that?

Margaret: I didn’t, but the birds plant it every year, again and again and again and again, because it’s everywhere around me in the edges of the woods, and so forth. But people maybe don’t know what are the invasives around them-

Ken: Well, there’s plenty of lists of them, too-

Margaret: And it’s great if you’re thinking of buying a plant also, it’s so great now—and this is what the internet is good for [laughter]—if you just put in the word “invasive” and the name of the plant that you’re thinking of ordering, you will almost immediately get the result, state by state, of what states’ Departments of Natural Resources have declared that plant invasive.

And I mean this was a big aha for me, I don’t know how many years ago, in the last 10 years, about doublefile viburnum, which was the most popular viburnum when we were all starting to buy viburnums umpteen years ago. It was the one, the gateway viburnum, and now what’s the case? It’s seeded into the woodlands just like that Oriental bittersweet; it’s invading the woodlands in many areas.

So if you do a “doublefile viburnum invasive” search, if you search for those three words on Google, you’ll see what states have declared it an invasive, so it’s actually quite easy to check yourself before you make an investment, especially in a plant that sets a lot of seed or fruit.

Ken: Before you buy those barberries.

Margaret: [Laughter.] Oh, yeah. I think the other thing to do, that we can add to the to-do list, is look for spaces, like where there’s slightly more sort of stern eye, look around your place for spaces, like you talked about creating the Guilt Garden bed.

And I’ve said this before on the program, but I’ll say it again, because it’s been a real lesson for me: I was mowing up to the fence line all the way around my place, it’s 2.3 acres and I have a lot of giant beds, so it’s not all lawn by any means, but even though I have kind of a meadow in one area up the hill, I was mowing up to the fence line behind that meadow and to the sides of that meadow and so forth. And I found that if I came in even say 6 or 8 feet, stopped mowing around that 2.3-acre perimeter, came in 6 or 8 more feet, there was an opportunity for more plants than I can afford. [Laughter.]

Do you know what I mean? I could have a whole giant number of native viburnums and so forth lining that. You can create these sort of edge beds, these sort of borrowed edge areas—it might be up against a fence, or the neighbor’s property, or against a hedge, where you can steal back some feet that right now you’re just mowing it, and you could create a place for the winterberry hollies or the native shrubs, and a simple native groundcover.

Ken: And that can end up being less work for you-

Margaret: Totally, totally.

Ken: And as I get older, one thing I’m doing here is planting deciduous shrubs, native deciduous shrubs along those very edges—and some of them, you don’t ever touch. Plant them and forget them.

Margaret: Right. And then obviously islands—I’m cutting more sort of islands, amoebic-shaped islands, not taking up the lawn, but seeing what happens if I don’t mow it anymore, and I’m finding I’m getting these sort of goldenrod aster, little bluestem prairie grass meadow sort of islands, and I’m creating more of those [above, in late August at Margaret’s]. So that’s kind of fun too, it’s almost like instant gardens, and it obviously depends on what you had there. If it was pure turfgrass, you may not get what I just said [laughter], you may have to add plants-

Ken: Right. Well, do you think you’re going to be a succession manager and let those areas turn into woods?

Margaret: Up at the very top of the hill, inside the fence—outside my fence would be forest—I have for two years now, this will be the third year, stopped mowing to see what came up. And the beginning of the oaks, which are the best plant of all, native oaks, oak seedlings, plus native witch-hazel (Hamamelis virginiana seedlings), some of the mapleleaf viburnum (which I think is Viburnum acerifolium), and so I’ve been evaluating what the land wants to give me, do you know what I mean? What wants-

Ken: Yeah.

Margaret: … yeah, and I mean in some cases, it’s probably what a squirrel buried frankly, but whatever [laughter], or a seed that someone buried. And so now, Year 3, I’m going to thin a little bit of these little seedlings, and imagine then what’s going to grow at their feet, sort of looking at what’s coming up, there’s some ferns happening, so it’s interesting, again, I’m in a more rural area, so this wouldn’t necessarily work in a suburban Kentucky bluegrass expanse, you might not get so much diversity. But that’s what I’m doing, I’m observing what I have, and then thinking of adding other things that would complement or augment these islands that are being created. So, that’s what I’m doing. I don’t know, it’s my little experiment, Ken.

Ken: It sounds great, it sounds great-

Margaret: I heard, speaking of natives and non-natives—speaking of collectibles again—a little birdie told me that you ordered a snowdrop, a Galanthus, from England?

Ken: A single, small, non-invasive-

Margaret: No.

Ken: … talk about collectors. I bought one of the least expensive English Galanthus, which are snowdrops, blooming now. And it was about £12, and the shipping was more than £12-

Margaret: 12 pounds in money, not 12 pounds in weight? [Laughter.]

Ken: Exactly, correct. And it’s beautiful, and I hate to tell you the name of it, but it’s Galanthus ‘Trumps.’ [Photo above by Ken.]

Margaret: ‘Trumps?’

Ken: Mm-hmm.

Margaret: Oh my goodness.

Ken: I don’t know why. But it’s beautiful, and I didn’t buy it because of the name, I bought it because it was in this list, where some of them were $125-

Margaret: Wow.

Ken: … for one little bulb-

Margaret: One bulb?

Ken: Yeah.

Margaret: Yeah, so snowdrops are super-collectible, the thing I can never tell the … this sounds terrible … but I can’t tell the difference between them, because you kind of have to crawl around on the ground to tell.

Ken: Well, I actually have a telescoping dental mirror-

Margaret: You have a what?

Ken: [Laughter.] A telescoping dental mirror … no, I haven’t used it, but I think if I ever had a Galanthus collection, which is completely unrealistic because it costs too much … I have this little dental mirror, that’s on a telescoping wand, it clips in your pocket like a ballpoint pen-

Margaret: So you can look under the flower and see which one it is?

Ken: Yeah, so you can see what it’s like without getting your stomach wet.

Margaret: All right, well he’s still collecting, but he’s also making room for more natives: That’s Ken Druse, thank you Ken, I’m so glad to speak to you as always. We’ll compare some more notes soon, yes, yes?

Ken: Yes, yes.

Margaret: All right.

which native plants match your site? some references

• Go Botany (New England regional), from the New England Wild Flower Society
• Native Plant Finder from National Wildlife Federation, University of Delaware and U.S. Forest Service (searchable by Zip Code; launched 2018).
• Atlas of the Flora of New England by Ray Angelo and David Boufford of Harvard. Doesn’t specify native, but does mention if the species’ origin from other countries/continents is known.
• Calflora (California), of native and non-native plants, including the ability to search by plant name or by location–so for instance to explore the plants of a park, or other area you might be visiting.
• Native Plant Information Network (National, Ladybird Johnson Wildflower Garden): Get an alphabetized list of all the plants (8,593 species) on which they have data, then narrow your search to a particular state.
• New York Flora Atlas: search for a list of plants recorded for a particular NY county. (The New Jersey one, as another example, is here.) You can then restrict that list to native plants or non-native plants. For other states try starting at…
• …a list of state wildflower societies, from American Horticultural Society. The state societies will probably provide a link to the state flora database on their websites.
• Vascan, a searchable online atlas of the vascular plants of Canada, will show a map along with nativity status, and allow you to create a province-based checklist.
• The Biota of North America Program (BONAP) allows you to map species to county, for each state, and  search on a particular species and understand what its distribution is, native and non-native. Coming: tools that allow you to create a checklist for your own county.
• The USDA Plant database, including maps and the ability to search by state, for example.
• Missouri Botanical Garden: The Missouri Botanical Garden and more than 30 U.S. and Canadian institutions are collaborating on a printed and computerized inventory of the 21,000 species of plants of North America north of Mexico. Dr. George Yatskievych oversees the program and is director of the Flora of Missouri project. World project aiming for completion by 2020. Work to date is at the Flora of North America website, and will be published in print as well.
• You can also use MIssouri Botanical Garden’s Plant Finder, which specifies native range in the results of each plant description (but doesn’t include maps).
• NatureServe Explorer: Searchable database on 70,000 plant, animal, and fungi species, updated in 2016.

prefer the podcast version of the show?

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 February 24, 2020 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).