Proponents for growing native plants, especially in gardening, argue that because native species adapted and evolved in their surroundings, they are best suited for the climate, habitats and mutually beneficial relationships with species in the area. But does this still ring true as our planet continues to change? Can someone have a garden that mixes both introduced and native species that still benefits insects and animals? Ferris Jabr is a science writer and author of “Becoming Earth.” He set out to answer these questions in a new piece for the New York Times. He joins us to discuss the native plants movement, its challenges and benefits.
Note: The following transcript was transcribed usingAI and validated for accuracy, readability and formatting by an OPB volunteer.
Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. Proponents for growing native species in home gardens argue that this plant life is best suited to foster mutually beneficial relationships with other native species. But does this still ring true as climate change changes habitats? Can a garden that mixes native and introduced species still benefit insects and other animals? Ferris Jabr is a science writer and the author of “Becoming Earth.” He has been exploring these questions in the context of his own Portland backyard, and he wrote about his journey in a new piece for The New York Times. He joins us now. Ferris, welcome back to Think Out Loud.
Ferris Jabr: Hi, thanks for having me.
Miller: Can you describe what your Portland backyard looked like when you bought your house six years ago?
Jabr: Back then, the backyard was literally just a crispy, patchy, rectangle of grass. There was almost nothing else back there.
Miller: You write that the decrepit yard would have been a turnoff for some prospective buyers, but for you and your husband, it was a feature. Why?
Jabr: We already had in mind this dream of creating a garden from the ground up, and so to us, the basically dead grass lawn looked like a really great blank canvas on which to do that.
Miller: What kinds of priorities were you balancing?
Jabr: So, we wanted the garden to be a place where we could relax, entertain friends. We wanted to grow fruits and vegetables, but we also definitely wanted to provide habitat and resources for wildlife. So we were trying to balance those different priorities.
Miller: What did you plant in the first few years?
Jabr: We ripped out all the grass. We put some raised beds in the back for vegetables. We put some fruit trees along the fence, and we reserved an area near the front for lounging with just a very simple green ground cover. In the much larger middle section, that is where we planted all kinds of hardy drought-tolerant flowering perennials, things like choreopsis, sedums, penstamen, sea holly, and these were all plants that were pretty darn hardy, good at taking care of themselves, but they came from all over the world.
Miller: Three or four years in – and in fact, I think you and I talked four years in, two years ago when your book came out – what was the garden like?
Jabr: Back then, the transformation was already quite marked. It happened really fast, much faster than we expected. I think when you give plants that space and opportunity and time, they really surprise you and astonish you with how much they can do on their own. So things had really filled in by that point, and I was starting to learn more about native wildlife and starting to document and record the different species that we were getting visiting the garden.
Miller: Can you give us a sense for the diversity of bees as one example? I mean, who was living there or visiting there in the bee world?
Jabr: Right. So, when I was growing up, I only thought there were honeybees and bumblebees. I didn’t even realize there were more bees. And it turns out there’s something like 20,000 different species of bees around the world. I think we have around 4,000 or more in North America. Most of these bees are tiny, solitary. They live in burrows or in cavities in wood. They don’t make honey, they’re not colonial, and they rarely sting. And they range from glittering green sweat bees to giant fuzzy orange bumblebees to tiny metallic blue mason bees. And we were getting dozens of native bee species visiting the garden after just a few years of converting the lawn to a very diverse flowering mix.
Miller: What about other insects or animals?
Jabr: We saw some dragonflies and water skimmers were some of the first to arrive because we put in a pond and bog. We got butterflies, beetles. Then we got larger animals, like all different kinds of birds, not just songbirds, but hummingbirds, and even the occasional bird of prey would stop by, like a small falcon or a merlin. And then we even had a few mammals, like this mischievous family of raccoons that came to the pond almost every evening and held some sort of raucous party there, because I would find the aftermath of that in the morning with all these trampled plants around.
Miller: So as you’re describing this, it seems like a wild success. But you write that as you engaged more with like-minded gardeners, your confidence “wilted,” that’s your word. Why? What were you hearing and how did it start to change your understanding of what you were in the process of creating?
Jabr: So the more I learned about wildlife gardening, especially here in Portland, the more I was hearing about the importance of native plants, growing plants that have long evolutionary histories in the particular region they inhabit. So, plants that have been here in the Pacific Northwest for thousands upon thousands of years. And I had sort of been aware of that importance in the beginning, and we have included some Pacific Northwest natives, but it was not our priority.
I was really focused on hardy plants and plants that had lots of profuse blooms, not specifically native plants. And I started to understand that there are particular ecological relationships between native plants and local wildlife that cannot be replicated or substituted for by foreign species. And so it seemed to me that I’d missed sort of a giant slice of the biodiversity pie. I was supporting some wildlife, but there were a whole bunch of others that I was not really sustaining in the way I wanted to.
Miller: What kinds of questions did you have once you started feeling this pressure to plant more native species in your backyard?
Jabr: There was a bit of tension in my mind because I could sort of understand why natives would be important for certain types of creatures, but at the same time, we’d already observed so much wildlife. And then I was also thinking that the environment we’ve created, that our species has made in today’s world, is so drastically different from what was around thousands of years ago that I wasn’t 100% convinced that those sort of ancient co-evolutionary relationships would really be that important. So, I really wanted to understand more of the general underlying science, see what the latest experts had to say about this movement and this kind of thinking.
Miller: All right. And to answer some of those questions, you decided to spend a couple of days in Pennsylvania with a man named Douglas Tallamy. Who is he?
Jabr: If you spend even a little bit of time reading about native plants, you’re probably gonna hear about Douglas Tallamy. He is an entomologist, and he’s kind of the de-facto guru of the native plant movement and its leading advocate. He has done three decades of research demonstrating that native plants really do support more native wildlife species, in particular, large long-lived species like native trees and shrubs. And in tandem, he spent close to 30 years restoring the ecosystem around his home in rural Pennsylvania, turning it from a tangle of invasive shrubs into something much closer to a native woodland. And he’s now recorded close to 2,000 native moth species and more than 60 native bird species breeding on his property.
Miller: Can you describe just what it was like to walk around and really spend days and nights on his property?
Jabr: Yeah, I think the first thing to understand is that when they bought the property in 2000, it had been a farm. It had been mowed for hay. It was a very flat, treeless expanse, and it was completely covered in tangles of invasive shrubs, like multiflora rose, oriental honeysuckle, and so forth. So they had to get in there and rip out all those invasives and start welcoming back in the native trees and shrubs. So now when you go there, almost 30 years later, it literally feels like walking into a native forest. There are giant stands of beautiful native trees, oaks, and beeches, and cherries and plums. There are all kinds of beautiful understory plants like azalea and sassafras.
And you cannot walk more than a few steps without running into some sort of wild native creature. We even saw phenomena that Tallamy had never observed before because there’s so much happening, like carrion beetles that normally feed on decaying flesh, instead, eating the sap from an oak tree for some reason. Or we found this large congregation of native bees that had just emerged from their underground burrows, and they were buzzing around waiting for the chance to mate with the females that were also about to emerge.
And in the evenings, we set up these special lights that attract moths and other insects. And hundreds of moths came out of the dark wilderness. They congregated where the light was, and we saw one of the most spectacular moths in our country, the Luna moth. It’s a massive absinthe green moth with these beautiful looping tails, and it just came crashing down through the canopy. I’d never really seen one that close before. So to witness all of that was truly inspiring and I think that’s a big part of why Tallamy has inspired so many people.
Miller: He’s written, and you quote this, “Increasing the percentage of natives in suburbia is a grassroots solution to the extinction crisis.” What does he mean?
Jabr: Because native plants and insects have these really tight co-evolutionary relationships, most of the leaf-eating insect species around the world can only digest the particular plants with which they co-evolved in their native homes. And basically, the rest of the plant kingdom is off the menu for them. So if we have these gardens that are mostly lawns and then are filled with these foreign species that native insects are not able to eat, we are depriving the native insect life of the food they need. And then all the other animals depend on insects because they are by far the most numerous kind of animal out there.
For example, a clutch of chickadees needs their parents to feed them about 3,000 to 5,000 times in just over the course of 16 days from hatching to fledging, and most of those feedings will be caterpillars and other insects. So if you take that away, you start this cascade of biodiversity crises where all these animals that are depending on the insects aren’t getting the sustenance they need. So Tallamy’s argument is that we really need to stop planting foreign species in our gardens, prioritize native species, reestablish those local food webs, make sure we are not severing those really fundamental ecological links.
Miller: You note that it’s not quite as simple always as “native plant good,” “non-native plant bad.” What are examples of some introduced species contributing to a stable and diverse ecosystem?
Jabr: Right. So it’s important not to think that a non-native or introduced species is synonymous with an invasive or harmful species. Most of the species that have either moved around on their own or that we have moved around do not become invasive or problematic, but there is this small portion that really does. In other cases, however, we do see that introduced species actually have some ecological benefits or are just kind of neutral. So, for example, one of the most famous examples is the anise swallowtail. When fennel came over from Europe, the anise swallowtail butterfly found that it could breed really well on this introduced plant that had similar enough chemistry to its native host plants.
And actually, some groups of anise swallowtails now produce additional generations every year because they breed so well on that introduced species. Likewise, eucalyptus trees from Australia are up and down California, and monarch butterflies, when they’re migrating along the West Coast, actually will often rest and shelter in eucalyptus trees. They’re tall, they provide good shelter. They have the kind of leaves they can cling to, and they’re often blooming in the winter when there isn’t much other nectar around. So, there are examples in which introduced species are providing certain types of benefits for local wildlife.
Miller: There’s also the question of time that you get into. You write this, “From a deep time planetary perspective, there’s no distinction between native and non-native.” What do you mean by that?
Jabr: I think it’s important to remember that the kind of ecological belonging we’re talking about is absolutely meaningful on the more relatable timelines that are relevant to us, our communities, our societies. But if we step back and we take this much broader planetary geological perspective, it doesn’t really make sense to talk about native and non-native anymore. Think about, for example, a newborn island in the middle of the Pacific that literally has no life on it whatsoever. It’s just erupted from the inner magnetic earth, and it’s completely barren. It has to be populated by creatures that come from elsewhere, whose evolutionary histories lie elsewhere, and over time they will adapt to that environment and become the first wave of native species. But that is how life populates new biomes throughout our planet’s history. So I just think it’s important to keep in mind that what we’re really talking about is native and non-native on more relevant shorter time scales, not in this planetary geological sense.
Miller: And then somewhere in between those two scales, but a lot closer to the human lifetime one, is climate change and the massive changes that it is bringing. How do you think about climate change in the context of this conversation about native versus non-native or introduced species, even just in your own backyard?
Jabr: This is where it gets especially challenging because the rapidity, the swiftness of the changes we have introduced are really unprecedented in our planet’s history, and there are many native species that are struggling to keep up with those changes. So, there are cases in which it may make sense to very strategically incorporate some introduced species. For example, let’s say you live in a really hot and arid part of California that’s becoming even more drought-prone and hot. And you need a street tree. You need a tree that is relatively compact, that doesn’t spread around too much, that provides good shade. And there really isn’t a native tree that meets those criteria, but there might be one from a nearby region that does, that handles that extreme weather, those extreme conditions a little better, and is also helping local wildlife at the same time.
Some experts think that we should be open-minded enough to include those kinds of choices. And introduced species are also particularly good at handling these kinds of asynchronies and gaps that can result from climate change. For example, climate change is shifting the rhythms of our plants, and that means the pollinators that co-evolve with those plants are starting to get a little confused about when things are supposed to be blooming or not blooming. So often you’ll have these gaps in the bloom sequence across a whole year, where either things are being mistimed or there just aren’t any native species that are really blooming at that particular part of the year.
So you can have some introduced species that fill those gaps, that expand the resources for pollinators, and that contribute to supporting local wildlife. So, I do think that if you want to support wildlife in your garden, focusing on natives, prioritizing natives makes a lot of sense, but you can also strategically incorporate some introduced species, and I think we have to be flexible, open-minded, and adaptable in this time of rapid change.
Miller: Your piece is not a how-to guide or a set of directions, but you do offer a helpful way to, in some ways, get past this binary of native versus non-native. You say that one of the more specific and relevant questions that an ecologically-minded gardener can ask to the plants that they might put in their garden, is not where are you from, but what will you do? What do you mean by that?
Jabr: Right. So, I think understanding whether a plant is native or not, its origin, that is a great heuristic. It’s kind of a shortcut for understanding how likely is this plant to integrate with my local ecosystem? If it’s native, it’s probably much more likely to do so successfully. But we can get a lot more specific. I think one of the great joys of gardening is learning to know the plants and wildlife around you as individuals, as truly as your neighbors, getting to understand their behaviors, their rhythms, their personalities and preferences.
Every year, I learn the microclimate in my garden a little better. I start to know when certain bee species are going to arrive, what months they’re going to be there, what times of day they prefer to be out there, when their favorite plants are blooming and not blooming. So, I think we can start asking really specific questions about our plants, such as, what effect are you going to have on the soil? What specific animals are you supporting? How are you supporting them? Are you providing shelter or sustenance, or both? Getting into those kinds of details, it is a true joy because you understand that these aren’t just commodities or ornaments that you can just shuffle around however you want. These are living members of your community, and you’re really working together to create this landscape.
Miller: You’ve started to shift then what you’ve planted in the last couple of years as you’ve become more attuned to everything we’ve just been talking about. What kinds of shifts have you noticed in the garden as a result?
Jabr: So, if I could go back in time and start over from the beginning, I think I would have focused on large structural, architectural native plants first, like some really good native trees and shrubs, and then I would have planted around them with some native grasses and native flowering perennials, and then I would have woven in my favorite introduced species in the pockets that remain. And so what I’m trying to do is kind of do that retroactively, because I’m not willing to rip everything out. There’s too many wonderful established plants and habitat back there.
But I do see many cases in which there are native plants that could work better than some of the introduced species that are in there in terms of supporting wildlife. And I have already brought in seven compact native trees and shrubs, and dozens of native flowering plants. And I think we now have more than 40 native species, all told, of plants. And I thought it was gonna take at least a couple of years to notice a difference in terms of the wildlife. I’ve been shocked at how fast the changes have happened. I can’t remember ever seeing a single caterpillar in my garden.
And just in the past month, I’ve found a caterpillar of a native butterfly and a huge green caterpillar that belongs to a native sphinx moth, the white-lined sphinx moth, also known as a hummingbird moth, cause it’s so large that people sometimes mistake it for a hummingbird, and it’s actually breeding in our garden now. It’s found enough host plants to do that.
We also set up a birdhouse for chickadees years ago, and it’s been empty this whole time until this spring when some black-capped chickadees chose to nest in there, and we watched them foraging caterpillars and spiders and other creatures to feed the nestlings, and they successfully fledged their clutch, and now those fledgling chickadees will fly through the garden and visit on occasion. And it’s been such a joy to see them and to know that we could just contribute in some small way to that new generation.
Miller: Ferris, thanks very much.
Jabr: Thank you.
Miller: That’s Ferris Jabr. You can see his new essay in The New York Times. You could also find our earlier conversation. We talked at the 2024 Pickathon Festival about his book “Becoming Earth: How Our Planet Came to Life.”
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