When I spoke to nature writer and naturalist Nancy Lawson about her recent wildscaping adventures at her Maryland garden, I was particularly interested in one particular topic. Her tactics for combating unwanted weeds and invaders as we loosen parts of our landscapes by adding more native plants.

I wanted to know more about the plants that Nancy uses to outcompete the unwanted ones, such as the native perennials.

 “The Humane Gardener” and most recently “Wildscape”, stresses that we are not alone in this world and advocates animal-friendly gardening and maintenance techniques. She uses a combination of scientific research findings and her personal moments of discovery while creating her own wildscape to help us tune in to everyone who lives there.

You can listen to my podcast and public radio show from June 12, 2023, using the player below. Subscribe to my podcasts on Apple Podcasts, Stitcher , Spotify, and Stitcher. You can also browse through my archives of podcasts.

Natives are fighting weeds with Nancy Lawson.

Play this episode Margaret Roach: Thank you for returning to speak to me again, Nancy. It is greatly appreciated.

Nancy Lawson, Thank you for having me. This is a great topic and one of mine as well.

Margaret : Do you like weeds?

Nancy: Native weeds are my favorite.

Margaret: okay, Yes, I just had a garden day. It’s a spring ritual to prepare the garden, whether or not you have visitors. Mulch, clean up, etc. It’s now time. I’m sure many people are in a similar situation. It’s almost the right time to go back and tackle some of those more significant battles we know we’ve all had in our gardens. Everyone has something. What are your biggest challenges at home? You’ve lived in the same area as me for a while, with a similar land size. What are your most annoying constant companions?

Nancy: Yeah. Well, the Stiltgrass (Microstegium Vimineum), is one. It will grow in small pockets almost anywhere. Another one I had a successful battle with was the mugwort.

Margaret: Oh, yes.

Nancy: Yeah. My husband’s grandfather grew heirloom asparagus in his garden. I knew it would come with mugwort, and it did. We didn’t manage to control it. After a while, it was a 30-foot-by-10-foot area of mugwort.

Margaret: Yes, yes. Isn’t that an [ Artemisia villosa]? I believe. Isn’t it?

Nancy: Yeah.

Margaret: Okay, it’s perennial Artemisia, and it is rhizomatous, also, correct?

Nancy: Yeah. When it gets going, there are these substantial orange-rooted mats. And I’ve had it in other places where there are already lots of plants, and in those places, it’s elementary to just pull. But this was a place we had specifically dug out for asparagus and not put much other things. And it was always just my last thing to get to because there was so much else to do. And whenever I would try, there were lots of ladybugs in there.

And then one year, I noticed that there were walnut trees coming up in it, and there were black raspberries that actually really seemed to be competing with it. And so that gave me some encouragement. Those were my bright spots to start from. And I guess it was right before the pandemic when I started just taking it on for real. And I did a combination of smothering it with cardboard and wood chips and then also… But I don’t want to just do that because then stuff comes right back, you know?

So I also started planting other things that grew in a similar way, like Jerusalem artichoke, mountain mint [Pycnanthemum], these things that could really take over the ground in the shady part, the golden ragwort, the robin’s plantain [fleabane, Erigeron pulchellus], and these other things that would really either shade out germination of the mugwort seeds or compete directly with the roots.

Margaret: And so how did you kind of figure that out? Do you know what I mean? Did you just observe who was doing a good job elsewhere? Where do you get that kind of insight?

Nancy: So I started just looking at this sort of subject matter, I guess, probably about 12 or 13 years ago when I had garlic mustard a lot in a certain area. And I left some plants out of golden ragwort[Packera aurea], and I was going to give them to friends. And then I came back the following spring. This was in the fall, I guess I had dug them up, and I found that they had rooted out of the pots and into the golden ragwort and saw they were competing with it.

And then I learned about plants like clearweed [above, as a groundcover at Nancy’s; detail at Margaret’s below], that actually there’s been research showing that they are… They can directly compete with garlic mustard chemically.

Margaret: That’s a great plant, Pilea pumila. It’s a great plant, and people think it’s a weed because it has that “weed” suffix in its common name, but it’s an important… For certain moths or butterflies, I believe it’s a host plant, and it’s a great plant.

Nancy: It’s beautiful.

Margaret: So it’s interesting to hear that it also has a scientifically proven ability to help us with these types of problems.

Nancy: Yeah, it can go head-to-head. And so seeing that sort of research makes you wonder, well, what other plants can do this?

Margaret: I see.

Nancy: And obviously, the ragwort can do it, and then thinking about not just their chemical properties, but their growth habits. And one of the reasons that the ragwort does it, at least where I live, is that it’s also usually pretty evergreen. And so it’s competing not only chemically, but it also has this ability to leaf out before anything else, or already be leafed out, depending on where you live. And so it can shade out the germination of the garlic mustard seed.

Margaret: Well, and that’s how a lot of our what are now considered invasive plants in many areas that came from other nations, that was one of their traditional sort of edges, why they became so successful when they came here, and similarly where our plants went to other places as plants have moved around the world, is that they frequently leaf out sooner than the local stuff [laughter].

Nancy: Yeah, exactly.

Margaret: And that’s a great… You’re right; that’s great… So looking for those types of qualities, but not in an invasive obviously, looking for those kinds of qualities that can help to stifle the unwanted. I see. So that’s what you were doing.