the garden as habitat, with doug tallamy
THINK 3-D, SAYS DOUG TALLAMY, co-author of “The Living Landscape,” and in fact, maybe think 4-D, since by designing your landscape in all three dimensions, layering plants into complex communities, you’ll add the “D” of diversity, too.
Entomologist Doug Tallamy and his wife have spent 14 years coaxing back to life 10 acres of what had been farmland for nearly four centuries: achieving more diversity by adding layers to its once-flat botanical architecture. Today 54 species of birds nest on their Delaware property, and acorns the couple planted have become 20-foot trees–so many that now editing is required.
Tallamy, professor in the Department of Entomology and Wildlife Ecology at the University of Delaware-Newark, has been called the “guru of the habitat gardening movement.” He is co-author with Rick Darke of a new book, “The Living Landscape: Designing for Beauty and Biodiversity in the Home Garden,” and he joined me on the radio to talk about just that. Enter to win a copy, but first get a primer on building “the specialized relationships that are nature,” as Tallamy calls them, like these:
Think, as he does, about having something blooming every week from earliest spring through latest fall so pollinators have a steady diet; about creating more dynamic edge or ecotone in your garden (and reducing your contribution to America’s 45.6 million acres of un-diverse lawn); about making more insects happy because insects make the world go round.
Making a garden is not merely outdoor decorating, is it?, I asked, as we began our chat (listen in now).
“Plants do so many things, and if we only look at what they look like—if we only look at their decorative value—then we’re ignoring all those wonderful things they do, and we actually pay a heavy price for that,” he said.
Q. Your preface of “The Living Landscape” speaks to the possibilities of this gardening approach (and reminds me of my place and what has happened over the years). Tell us your home landscape story. [That’s Tallamy up in the canopy bug-hunting, above; photo from Uinversity of Delaware website.]
A. We live on 10 acres. It was one of those farms that was chopped up and sold. We were looking for a more rural situation, so we grabbed it and put a house on it. It had been mowed for hay forever when we got there, and was taken out of mowing three years before we moved in, and what returned was not the grasses that they were mowing, but all the woody invasive species that are really common in our area.
Q. I think I remember that stage at my place. [Laughter.]
A. I used to say it looked like Sleeping Beauty’s castle—you couldn’t even walk around. It was just choked with everything.
Our immediate goal became controlling those invasives; first we cut paths so we could walk around, and see what was out there. It’s been a constant upkeep trying to keep those plants out.
In the meantime we encouraged the return of natives. I did not record what was living on that property when we moved there, but now we have 54 species of birds that breed there—just about all we can probably squeeze in—and we have put many, many plants back, mostly woody, because we are returning it to the Eastern deciduous forest that it wants to be.
We do have meadow sections, but the focus of the landscape has been on restoration, not fancy landscape design. The fascinating part of this restoration is to see all the things that have come back. We’ve been there 14 years now, and every year we see new things that we hadn’t before.
If you provide insects, all the things that eat insects will show up.
Q. I love what you say in the book about who shows up—when you’re managing, or in some cases not managing, the landscape. Each year seems to have its starring characters. This has been the spring of the giant millipedes, Narceus americanus [above photo] for me—like I had a marching band of them; they were on parade. Maybe the way I try to keep all the good organic stuff in place—good leaf litter and mulch on the beds—was a factor.
A. And you probably had a fair amount of rain last year. All these things come together and you get population growth. Every population in the world goes up and down, depending on whether the conditions are good or bad.
We as entomologists have been trying to predict when that will happen forever—and we’re not very good at it. [Laughter.]
Last year at our house, I called it the year of the caterpillar–and up and down the East Coast, everyone was talking about them. I saw caterpillars I hadn’t seen in 10 years. In August, I stood under one of our young oak trees that I started from an acorn and looked up, without moving, and I saw 11 caterpillars that were in six species. I hadn’t seen that kind of diversity before.
Q. I’ve become more attuned to moths since a field guide to them came out a couple of years ago, and it’s amazing how many I can see in the garden without even really looking. [Those are the small tolype moth, left, and clymene, right, in the photo below, in my garden.]
A. The addition of these books to our libraries has been wonderful. It has made some of the most common animals that we have, accessible to everybody else. No longer are they just “worms” or “ugly moths,” but we can put names on them, we can recognize them, we can understand what they’re eating, why they’re there, who depends on them. All of these things become accessible to us, because we know who they are; they’re our friends.
Q. So speaking of what they are eating—you said you’re emphasizing native plants in your own landscape, but I was glad to find in “The Living Landscape” that you have a practical way of thinking about the definition of “native plant.”
A. It’s a functional definition, as opposed to a geographic one. A lot of people think a plant that’s native to North America is a native—but that would make a plant that’s native to California native in Delaware, and ecologically, it’s not.
We’re not trying to make native-plant museums—to gather them all and plant them and look at them—but we’re trying to rebuild native plant communities that co-evolved together.
So our definition of native is a plant or animal that has evolved in a particular place long enough to be able to establish the specialized relationships that are nature. Most of the relationships between plants and animals are highly specialized, and they take a long time to develop.
This is the problem with moving plants around the world. They enter a new area where they have not had the time to develop those specialized relationships, so the local insects typically can’t eat them, and all the things that depend on those insects disappear as well, because there’s nothing generating those insects.
The plant may grow fine there, but it hasn’t developed those relationships that build community structure, and the diversity and abundance that supports these living landscapes. It takes time.
It doesn’t mean that our non-native plants will never develop these relationships, but we’re talking about many hundreds or thousands of years for them to develop—not a few weeks or a few years.
Q. A biologist friend who visited was surprised to see certain insects interacting with certain non-native plants here that are closely related to certain natives—and we assumed that meant they must be chemically very similar.
A. Yes, it must have the chemistry that allows them to recognize it as a host plant.
Let’s use the monarch butterfly as an example: Monarchs are declining; there is only 2.6 percent of their population left, essentially because we have removed milkweed, particularly in the Midwest. If insects could adapt quickly, they’d eat soy or corn or grass—but that’s not how it works. What will happen is that the monarch will disappear long before it adapts to a different host plant.
Specializing in one plant means you are unable to eat other plants.
Q. In “The Living Landscape,” you explain the layers of nature’s architecture, and I especially wanted to talk about one layer: “the dynamic edge” as you call it.
A. Think of your landscape as not just two-dimensional, where it has width and length. It also has height. It’s a three-dimensional landscape, and in the East here, for example, in the deciduous forest, you have a canopy of tall trees, a sub-canopy (probably the same species of trees that aren’t mature yet), and the understory trees (different species that form yet a third layer). Then you have shrubs underneath that.
What you have is vertical structure, and there are animals that specialize—in terms of where they live, where they hunt, where they forage—in each one of those structures.
Then of course you get to the forest floor, with all the perennials and ephemerals, and the leaf litter and all the complex soil organisms, and each one of those are vital layers of this kind of forest.
In our suburban yards we have come to worship the lawn, which is kind of uni-dimensional—well, it has length and width, but no height to it.
We have 45.6 million acres of lawns in the U.S.—eight times the size of New Jersey—that is dimensionless. When we put a tree in our yard we stick it in the lawn, which forms a canopy, but there’s nothing between the top of the tree and the ground.
Q. No transition.
A. Our goal here is to build more functional landscapes. We need to do that for watershed protection, to save the biodiversity that runs our ecosystems, to sequester carbon. We need to put the plants back.
We don’t have to eliminate lawn—it’s a great plant to walk on, and can guide us through the landscape, but we need to put a lot more plants in our landscape, and we need to do it not just two-dimensionally but three-dimensionally.
Q. And the edge?
A. Edge is a really productive part of all of these systems, because you have all these vertical layers but you have sunlight. You don’t have dark forest there. Where you get sun, plants funnel the Nitrogen to the growing parts of the plant (the areas in the sun, on the edge), and those are the most nutritious areas, generating the most food, so that’s where the birds hunt—we call it an ecotone. It’s a transition between two different kinds of systems.
Q. Yes—the edge. I know if I want to see the warblers in the morning, I go sit on the ground near the transition spots.
A. Our suburban landscapes are ideal for edge, because right now they’re so open. You can only improve it. [Laughter.]
Q. Some plants that you have used to bolster that edge–do we use small trees?
A. They can be small trees, or large trees that aren’t large yet.
Q. Here, I think of the shadbush (Amelanchier), the spicebush (Lindera), redbud (Cercis) as some of the plants for the edge—are those good ones?
A. Yes—and Cercis, for example, is a great plant for early spring pollinators. It blooms right when the first species of bees are coming out.
Pollinators are important in our ecosystems—obviously they pollinate. Everyone worries about the decline of the honeybee, which is not a native bee, but we have 4,000 species of native bees, many of which are in big trouble, just like the monarch, because we’ve taken away the flowering plants that support them.
One of the things we need to put back in our landscapes is a sequence of blooming plants right from spring through the decline in fall. Our native bees depend on a constant source of nectar and pollen, not just one week of bloom.
Look at your property any given week in the growing season, and if you don’t have something in bloom, it’s going to seriously impact any pollinators who try to live there. They have to eat every day—where are they going to go?
Q. As an entomologist, can you advise lay people like me how to become a better observer?As you said earlier, the new field guides on caterpillars and moths and such are a big help—but do I need a hand lens, or binoculars, or…? [I use my camera a lot; that’s a giant leopard moth caterpillar, above.]
A. If you have normal eyesight, I wouldn’t start with the tiniest insects, where you actually need a hand lens. What you want to do is develop what we call a “search image.”
There are so many things in your yard that are blending in with their background—they are cryptic. There are a number of caterpillars of Eastern red cedar (Juniperus virginiana) that look exactly like the needles of Eastern red cedar, for example. But once you develop that search image, your eye is trained to see the difference between the needles and that caterpillar, and they just start jumping out at you.
It takes a little bit of practice. You know, if you drop your contact lens on the floor, some people can find it right away, and some never can—because they don’t have that search image.
And most of the caterpillars, and most of the insects, are hiding underneath the leaves.
Q. So get underneath, and look up.
A. And another really productive thing to really get acquainted with what’s in your yard: Go out at night with a flashlight. So many things are on those plants at night that you don’t see in the day—in fact, most things. It’s safer to eat at night, because the birds are not hunting.
So those are tricks to expose you to the little things, the smaller life forms, that are in your yard.
enter to win ‘the living landscape’
I’VE GOT TWO EXTRA COPIES of Doug Tallamy and Rick Darke’s “The Living Landscape” Designing for Beauty and Biodiversity in the Home Garden” to share with you. All you have to do to enter to win one is answer this question in the comments box way down at the bottom of the page, after the last reader comment:
Where’s the wildlife action in your garden, and what are you doing to beef it up?
Me? My two little garden pools are a year-round source of activity for all manner of creatures, from frogs and snakes and salamanders to dragonflies, birds, various smallish mammals, and this summer, a very handsome gray fox. An unmown swath on the upper hillside is loaded with bugs, which means it’s also loaded with bigger insects (like voracious dragonflies) and birds.
No answer, or feeling shy? You could just say “count me in” or something like that, and I will, but an answer is even better. I’ll draw two random winners (U.S. and Canada only) after entries close at midnight Monday, June 30. Good luck–and good habitat gardening–to all.
prefer the podcast?
DOUG TALLAMY was my guest on the latest radio podcast. You can listen anywhere, anytime: Locally, in my Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) region, “A Way to Garden” airs on Robin Hood Radio on Monday at 8:30 AM Eastern, with a rerun at 8:30 Saturdays. Get it free on iTunes, the Stitcher app, or streaming from RobinHoodRadio.com or via its RSS feed. The June 23, 2014 show can be streamed here now. Robin Hood is the smallest NPR station in the nation; our garden show marked the start of its fifth year in March, and is syndicated via PRX.
(Credits: Bench photo by Ricke Darke, from “The Living Landscape;” photo of Doug Tallamy in treetops from University of Delaware. Disclosure: Amazon affiliate links may yield a commission that I use to purchase books for future giveaways. )