cornell’s take on the native lawn, with todd bittner

REDUCING THE footprint of our lawns has been a key environmental message for gardeners in recent years, since lawns lack biodiversity and involve huge amounts of pollution between fertilizers, herbicides, and the gas used in mowing. But what to cultivate instead? That is the subject of a nearly 15-year native lawn research project at Cornell Botanic Gardens in Ithaca, New York, with some interesting insights.

Todd Bittner is a plant ecologist who, with his Cornell Botanic Gardens colleagues, began a quarter-acre research experiment back then known as the native lawn demonstration area.

“Please do walk on these plants,” a sign on a pedestal tells visitors, explaining that it’s a test of a mix of low-growing natives as an alternative to traditional lawn. In a conversation, he shared what they’ve learned along the way.

Read along as you listen to the Oct. 23, 2023 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).

cornell’s native lawn, with todd bittner

Margaret: Hi, Todd.  We caused a ruckus with the “New York Times” story we worked on together [laughter], and we’ll talk about that in a minute, but when you tell people you want to take away their lawn or suggest it, boy, oh boy, you get some upset people. We’ll talk about that.

But I wanted to just get a background a little bit, a short background, kind of what’s in your lawn and how did it begin? How did this begin? Because it’s very different from some of the other possibilities I’ve heard before.

Todd: Yes, it is different. We want to credit our horticulturalist here at Cornell Botanic Gardens, Krissy Boys, for coming up with the idea. But she was inspired in seeing some of these native species growing in these lightly disturbed areas in otherwise intact plant communities—state forest land where there were power lines going through, or the edges of lightly used roads, places that there weren’t herbicides and weekly mowing, old cemeteries, places like that—and found two species of Danthonia, Danthonia compressa and Danthonia spicata [below], commonly known as oat grasses, as being something that really loved those conditions.

That was the genesis of the idea with the native lawn, and from that, we added a few other forbs and some Carexes that we thought could tolerate some levels of trampling and some light mowing regimes, and that was the genesis of the native lawn that we developed 15 years ago.

Margaret: Right. So these Danthonia, this genus, which of course, Margaret over here had never even heard of [laughter] and now understands because I’m in the Hudson Valley of New York and so I thought, “Well, if it’s native at Cornell, it’s probably native for me.” And sure enough, of course, and I probably have it all over the place, but they’re bunch grasses.

There’s a number of different species around the country. There’s even one in California, Danthonia californica, that is recommended in some municipalities as an alternative to lawns. So it’s not just one species of this genus. And they’re naturally low-growing. As I said, they’re sort of bunch grasses as opposed to sort of spreading sideways, and they’re low. They stay somewhat low if you don’t mow them. How big would they get, a foot or more or what?

Todd: Yeah, they grow somewhere between 8 inches to maybe 16 inches or so for the grass blades, and then a little bit taller for the flowering culms. They’re cool-season grasses, so they like to come on early in the spring, and that’s kind of a prerequisite of having a green lawn in the spring, and then like to grow again in the fall like most cool-season grasses do. But they’re also very drought-tolerant, which is a key component of the native lawn, because we didn’t want to create something that had these significant environmental costs, like having to water it in order for it to persist.

So those functionally were some of the characteristics that we were looking for. And most of these grasses co-evolve with grazing regimes, bison and so forth, so they can actually be stimulated a bit to grow more with periodic mowing. But we prefer to keep the mowing heights a bit higher than your traditional lawns because we want the plants to thrive and flower and create wildlife habitat, which you really wouldn’t get if it was an inch or two crop, like most turf lawns are.

Margaret: Right, right, exactly. And so that is a little bit of an obstacle at first, and we heard in the “New York Times” story, in the comments section, we heard from some people, as I predicted, that want to know well, how the heck are they going to keep it mowed? Because even if it’s once or twice-a-year mowing, because their mower blade doesn’t go up to the recommended height that you suggested, which was 6 to 8 inches, they have to use a scythe or they have to use a weed whip or whatever.

But since it’s only once a year, it’s not that big a deal if we had to weed-whack our front lawn. I mean, not 20 acres, but you know what I mean? If it’s an average front yard type of area, that’s not that big a deal.

Todd: Yeah, the average homeowner definitely could use a scythe or electric weed whip, as you said. I like to suggest electric, as opposed to gas-power, given the carbon emissions that you get from gas-powered weed cutters.

But we are right now—after the post-establishment phase, which is about two years, two to three years—we’re probably putting in just about two to three hours a year on the maintenance as compared to the average US homeowner that suggested something like 70 to 100 hours for maintenance of your typical suburban lawn annually. It’s a lot of time that we put in and invest in these turfgrass lawns and doing it once a year or twice a year…

And honestly, the height is very adjustable. That’s our recommended height, but the average homeowner can tailor it to what their interests are. If there’s areas that they want to look a little bit more manicured, you could mow it more frequently, you can mow it a little bit shorter. Areas that you want to gradate into your flower gardens and back edges of your property, you could put in zero hours if you wanted to. We only suggest that because we’re expecting that people want to be able to walk on and recreate and enjoy their lawns or not have their dogs disappear as they are out in the back doing what dogs do [laughter].

Margaret: So you said before, you planted it with some other things. So Danthonia is the dominant genus. There’s two species of Danthonia, these oat grasses that you have made the dominant species in this native lawn, and you included other things.

And one of the other things that people who are thinking of making a shift in their traditional lawn—which is a monoculture typically, although sometimes it has clover in it or whatever, but pretty much monoculture—one of the things they have to adjust to is that it is going to evolve and not look the same every year forever and a day.

I think in the Times story, I used the word fluid, because with native plantings, they evolve, and some things fall away and don’t work and don’t survive after the first years, and some come in, they get seeded in or a bird brings them in or whatever [laughter]. So there’s change also. Hasn’t there been a change in the palette?

Todd: Yes, we’ve learned a lot as we’ve tracked it over the years. And our founding principles were based on how prairie restorations are done in the Midwest. And you need founder species that are going to get started and established very quickly and start to compete against the weeds. And then you have other species that might take longer to establish and you need to provide space for them as well. And you also need to tolerate the fact that there might be some non-native species; as long as they’re not detrimental, that is O.K. as well.

And we originally set a goal of having the total cover of the native lawn be 85 percent, and that’s about what we ended up with.

Margaret: So 85 percent native species, and the rest, as long as they weren’t harmful, could be non-native, is that what you’re saying?

Todd: Yeah. So just a bit of a clarification, if you look at like a square meter, the amount of plant material that you’re looking at, 85 percent of it is covered by native species and 15 percent of the cover of the area is non-native.

Margaret: So not the plant list being 85/15, but the actual square footage, the cover, the area of cover. Thank you.

Todd: Right, exactly. Because that 85 percent is the 85 percent that’s beneficial for our native insects and for carbon sequestration and biodiversity and all the rest. We have broken it down. I won’t get into that level of detail about what percentages by each of the different species.

But we started with somewhere around a dozen species of grasses and sedges and around a dozen native forbs. And by and large, about 80 percent of both continue to persist at our site. There’s a few that we lost.

Some of them, we understand, probably weren’t really good choices, like columbines that might not like to be mowed. And other species that were fairly abundant and well-established early on in this very low-growing, not highly competitive species group like bluets [Houstonia] and pussytoes [Antennaria], originally were fairly abundant and now have mostly dropped out, because the amount of plant cover and the amount of plant competition is so great that those low-growing species just don’t get enough light, they don’t get enough water, and so on, and have kind of dropped out.

So there is this fluidity to the mix. And to our delight, we realized that we had a lot of species that we hadn’t included that were native, that came in and grew spontaneously from adjoining natural area habitat that we have. Violets being one of them, several species of asters and goldenrods, wind-dispersed seeds that were able to find a new home and establish in the native lawn. [Below, Viola sororia in the native lawn mix.]

Margaret: Yeah. So around the country in recent years, more and more projects, both research projects and landscape designers trying it and just homeowners, gardeners trying it: Lots of people have been trying lots of different things to reduce their lawn at least, if not eliminate it completely.

And you’ve mentioned Carex, the sedges, a couple of times, times, and people transition sometimes to a meadow. Some people look for alternative groundcovers that could go instead of the lawn. Some people transition to other kinds of lawn grasses that are low-mow, even if they’re not native, that require not the feeding and the herbicides and the mowing all the time.

So there’s a lot of ways to go. But so you chose the Danthonia thanks to your colleague having this inspiration and it’s not a seed that I see in a box on the garden-center shelf yet [laughter], but you’re also participating in helping that someday become something that’s more widely available, yes?

Todd: Yes. So we’re very interested in creating a custom mix with the Danthonia species to make it as easy as possible for homeowners to be able to make this conversion. That’s something that requires the public’s interest—which I think given the response to the “New York Times” article, is definitely there—and commercial nurseries that are interested in working to make that happen. There’s an opportunity here for us to work with Cornell Cooperative Extension to provide tools and resources towards that end, so we’re looking to pursue that as well.

And just this year, we discovered a fairly robust population of Iand collected over 3 pounds of that seed. So we’re working to create founder plots to upsize the quantity that’s available. And we’re planning on what I call the native lawn 2.0—I’m happy to get new ideas, a better name for that—to incorporate this next research pilot for us, using some of the seed that we collected. And intentionally including some of the species that grew spontaneously and others that we feel that are in commercial production that will do well in a revised species list for our next native lawn demonstration project. So we’re kind of working to tackle it on a few different camps.

Margaret: Yeah. That’s great because that’s obviously important, and hopefully other efforts around the country… We should say that one of the two Danthonia species that you chose, D. spicata, it’s very, very widespread. It’s present in parts of states throughout most of the country. So it’s not only for Ithaca, New York, is all I’m trying to say.

And as I mentioned before, there are other species that are also particular to different areas of the country, like a California native species and so forth. So it bears some looking into, through native plant societies in different areas if people are listening from different places.

But I want to talk about the comments [laughter] on the “New York Times” story, and I’m sure the comments that you’ve overheard sometimes as people have, over the years, visited the native lawn demonstration area, the project at Cornell.

Because every time I write about alternative lawns, I get sort of a few subsets of comments. One is, “I’m going to get tick bites” if they don’t just have a close-mown lawn. The other is, “Where will I barbecue/where will my children play?” And then the third group is often, “My homeowner’s association won’t allow it.” Those are three loud clusters of voices that I often hear.

Now, it’s not my understanding that grass is a primary tick habitat anyway, but that said, do you get the same kinds of worries? Do you hear people saying, “What about this? What about that?”

Todd: Yeah, I was really surprised by the number of comments about restrictions with homeowners associations limiting that. It was quite eye-opening to see. And I recall that there was even a lawsuit in Maryland, and they ended up changing the law over that, because people were trying to native-scape their home.

So yeah, I was quite surprised by that. And I think that it is a really unfortunate situation. I encourage people to run for their homeowners association and change those bylaws if you are interested in native plants and biodiversity.

Margaret: And to talk to your neighbors because if you’re in a community of, I don’t know, 100 neighbors and 20 neighbors suddenly decide they want to do this, if you’re all friends and you know each other and you all want to do it, bring it up to the HOA and see. Do you know what I mean? A consensus can be very, very compelling. It’s O.K. to do that.

And we’re not saying to make everything look a big old mess. That’s not what we’re saying. We’re saying still within this contextual aesthetic of a lawn—not as short a lawn, not as manicured a lawn, but a place that looks like there’s some care been given to it.

Todd: Yep, I agree. And the response is about, “I won’t be able to do the activities that I like to do because it’s not turfgrass lawn.” Those are the same areas that just had pesticides applied to them and all these fertilizers and things like that, and so that’s a bit of my response to folks. I mean, it’s your own personal choice about how you want to landscape, but most people are doing it not just putting the environment at risk, but pesticides in their backyards where the family dog is and their kids are playing as well.

So think about the lawn more holistically and recognizing that you can not just have it all be cookie-cutter, all-turf lawn; keep some of it as lawn for those activities. But probably most of the square footage of people’s lawns isn’t being used all in the same exact way, so that could make an opportunity for people to think about it a bit differently.

Margaret: Right. Yeah, that’s what I’ve been really experimenting with here in my garden is really looking more closely and critically at myself, at which parts do I need to mow how often? And even if I can, in some of the areas, go to every three weeks, or four-week mowing, and it gets to ankle-high or something like that. Do you know what I mean? Because I have certain areas where you have to go from here to there, because it’s the transition. Or could I let some of it go and make a path, a wide path through it, but leave 70 percent of it?

And yes, I have some areas that I’m always going to mow because there’s an area right adjacent to a patio and it is perfect for if people came over and wanted to kind of mill around and whatever and be on the patio and on the lawn. But it’s a small space and I can give back the rest. Do you know what I mean?

Todd: Yes.

Margaret: So I think you’re making a very important point is to really take a critical eye to your overall landscape and say, “Hmm, could this be the barbecue area and we’re going to keep mowing it? And could this be where the kids are also going to play? And over here we’re going to let it be looser.”

Todd: Right. I mean, most people don’t use their front lawns.

Margaret: Right.

Todd: So if the homeowner’s association isn’t restricting you, that’s not where you’re barbecuing.

To the first topic, which was ticks, that one is a legitimate concern. The amount of tick-borne diseases, Lyme disease being chief among them, is significant. It’s increasing in our area, and many people are affected by it, pets as well. There are a lot of tick predators in healthy ecosystems, and the idea that the tick population is going to be worse in an area that has potentially more tick predators in it than a turf lawn, I think is kind of a false narrative to begin with.

We haven’t seen any difference in the native lawn than we have seen in other areas, and we have deer ticks, and we have deer ticks with Lyme disease here in Ithaca. And the idea that promoting biodiversity that includes additional tick predators, things that compete for habitat with rodents that carry Lyme disease as well, I think having a healthier ecosystem is among the ways of trying to reduce tick diseases.

And now I am just speaking more broadly because we haven’t actually studied that but it would be my expectation-

Margaret: But I did an interview with some ecologists at Bard College, and Cary Institute, which is sort of nearer to me, but where they have… They alerted me to a lot of different research reports that do look into that. And what you’re saying is the gist of what I have been told.

I just wanted to—speaking of insects and arthropods and the biodiversity of the non-plant type: Some of your entomologist colleagues at Cornell came and counted and assessed who was present in this native lawn area, and it was pretty amazing, the numbers. Give us some of the numbers by comparison to a mown-lawn area.

Todd: Sure. Well, we looked at families of insects because sometimes identifying them down to genus or species can be a bit challenging. So we roughly had four times the insect biodiversity in The native lawn than we had in traditional turf lawns for the insects that were above ground, if you will.

But it wasn’t just the numbers of insects; it was the ecological roles that they each play. So we had herbivores, we had pollinators, we had predators, we had parasitoids. We found this diverse insect community with species in all these different ecological niches, and we didn’t really see that in the turfgrass lawns. We saw a lot of herbivores that basically like to eat some of the plants that are these Eurasian turf species that we have.

So when we’re talking about biodiversity conservation, we can all do a bit more and give nature a helping hand, particularly thinking about the climate crisis that we’re facing where we’re losing these species. And so it’s not just pollinators that we’re wanting to conserve, but the entire breadth of the biodiversity that is there, and the native lawn is one of the ways that we can do that.

Margaret: Yes. Well, it’s very interesting, and as I said, I was really struck by the response. I was so glad that we got a resounding response, even the naysayers, because it’s important. This is an important conversation to raise. And even if all that happens is that people think, “Hm. Well, maybe I could mow less frequently and stop watering as much. And maybe I don’t need fertilizer, maybe it’s growing fine without.” Even incremental changes can make such a big difference environmentally, don’t you think?

Todd: Particularly when you think about how much turf lawn there is in the United States. It’s 2 percent of the United States covered, equivalent to the State of Wisconsin. So if they all did… And it is something that most of us can do. Most of us that are homeowners have lawns, and so there’s agency there for us to do something positive for the environment.

So yes, even if it is less pesticides, no pesticides, no fertilizer, get an electric mower that has green energy that’s powering it and reduce the CO2 emissions—any and all of those things is moving in the right direction.

Margaret: Yes. Well, Todd Bittner from Cornell Botanic Gardens, thank you so much for both helping me with the Times story and for helping me with this podcast today, and I hope I’ll talk to you again soon and hear more about what you all are up to up there.

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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 14th year in March 2023. 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 Oct. 23, 2023 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).