Gardening goes deeper than growing your own food and enhancing the beauty of your surroundings — it can support your local ecosystem and contribute to the healing of our planet. This is the ethos shared by the gardeners, educators such as Dr. Doug Tallamy and ecology experts who will join me on May 8th for the inaugural Ecological Gardening Summit.
This online event, which will run from noon to 4:30 p.m. Eastern, will feature talks from entomologist Dr. Doug Tallamy of the University of Delaware, pollinator conservationist Emily May of the Xerces Society, ecological horticulturist Rebecca McMackin, former director of horticulture for Brooklyn Bridge Park, and Garden for Wildlife manager Mary Phillips of the National Wildlife Federation.
Doug Tallamy is a renowned entomologist and advocate for native gardening. He will join the Ecological Gardening Summit on May 8th. (photo: Courtesy of Doug Tallamy)
For this week’s podcast, I’m revisiting a previous conversation I had with Doug that touched on many of the ideas that the Ecological Gardening Summit will explore, and I’m adding new thoughts to the discussion.
This summit represents the culmination of years of learning and a heartfelt dedication to ecological gardening. It’s about transforming our practices to align with nature, rather than working against it.
Dr. Doug Tallamy
Doug holds both a master’s and a Ph.D. in entomology — the study of insects — and he’s a University of Delaware professor in the Department of Entomology and Wildlife Ecology. He has long studied the interactions between plants and insects, and the interactions between insects and the birds and other wildlife that eat them.
His books on the importance of conservation and native ecology include “Nature’s Best Hope,” “Bringing Nature Home” and “The Nature of Oaks.”
Doug has been a guest on the podcast to discuss why our plant choices matter, how you can sustain wildlife with native plants and why oaks are our most essential trees. Additionally, I visited Doug for season 10 of Growing a Greener World. We discussed the themes of “Bringing Nature Home,” including how non-native plants chosen for aesthetic and maintenance reasons don’t provide what native wildlife needs to survive.
“Caterpillars transfer more energy from plants to other animals than any other type of creature,” Doug points out. When caterpillars don’t have native plants to eat, they won’t be around to provide that energy to birds and other wildlife. A landscape without caterpillars is a dead-end for the food web.
The second time Doug joined me on the podcast, I asked him to share the most critical message from his blockbuster book “Bringing Nature Home.”
“It was exposing the concept that your plants are more than decorations, that they’re critical components of ecosystems because of what they do,” he says.
The book resonated with so many readers because he publicly drew a connection between the plants in our home landscapes and insects to explain why plant choices matter to wildlife.
“If you don’t have insects eating those plants and passing on the energy that they harness, the rest of the food web collapses,” he says. “And then we have biodiversity crises and all the things that revolve around that.”
Non-native plants are very poor at passing on their energy to native insects, he explains.
“So when you have invasive plants all over the country that are non-native, it creates huge food web problems,” he says.
When the book was published in 2007, this was news to the public, and Doug admits it was news to him too as he was researching the book.
In the 16 years since the publication of “Bringing Nature Home,” we’ve learned much more about the biodiversity crisis: global insect decline, the loss of 3 billion birds and a million species going extinct in 20 years.
“These are all headlines that are upon us now,” Doug says. “So the urgency to get everybody on board has increased.”
A prothonotary warbler with a caterpillar and spider in its beak. The insects that eat native plants will, in turn, become food for birds and their offspring. (photo: Doug Tallamy)
Powerful Native Plants and Mixing with Nature
Doug promotes native plants that are particularly powerful when it comes to supporting biodiversity. That idea inspired his book “The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees.” Oaks, which are trees and shrubs in the Quercus genus, are known as “keystone plants” because their presence dramatically increases ecosystem function. Keystone plants are the 5% of plants that create about 75% of the food, and in 84% of the counties in North America, Quercus is the No. 1 keystone plant.
Conservationist Aldo Leopold observed decades ago that the biggest challenge humans have always faced is living on a piece of land without destroying it.
“We’ve actually never accomplished that, but we’ve got to start,” Doug says. “What is the alternative?”
Mars is out there, but its capacity to support life is zero, he points out, so he plans to stay here and anticipates everyone else will too.
“This is an environmental issue where the individual can make a difference and see that difference,” he says of biodiversity. “You plant those powerful native plants at your property or somebody else’s property, you can see the life come and use them.”
Doug rejects the age-old notion that humans and nature don’t mix. The age-old practice of creating a subdivision is to eliminate everything that’s there and decorate it with non-native plants — mostly lawn. But he knows it doesn’t have to be this way.
“We have a finite amount of resources on planet Earth,” he points out. “If we take them all for human use — and that’s exactly what we’re doing — there’s nothing left for anything else.”
Those plants and animals that we share the Earth with provide ecosystem services that allow us humans to survive on this planet too, he says. “So it’s not an option to eliminate them.”
Humans have to get serious about discovering how to have sustainable interaction with plants and wildlife, according to Doug.
“The future is about restoration,” he says. “We didn’t leave it alone, but we can put it back together again. And some people argue about the word restoration. ‘Oh, you’ll never recreate exactly what was there.’ And they’re probably right. But what we’re restoring are interactions between the plants and the animals that used to be there. If they’re not the exact same interactions that were in that exact spot, that doesn’t matter. You’re still recreating the ecosystem function.”
Even a small oak tree can provide an abundance of food for birds that you’ll enjoy having in your yard, like this Magnolia warbler. (Photo: Doug Tallamy)
Rethink How Human Landscapes Are Designed
Human-dominated landscapes are designed to be very open, like savannas, dominated by lawn. The United States has enough lawn to cover New England and is still adding more lawn every year.
For a landscape to be ecologically functional, there are four things it needs, Doug explains:
Support the Food Web: A functional landscape must have plants that pass energy on to other organisms. Lawns don’t do this, especially when they are treated with insecticides.
Manage Watersheds: Plants are the best way to manage water on landscapes. Huge rain events, which have become more frequent and severe due to climate change, dump water that can cause flooding and stormwater pollution of water bodies if it’s not managed. A property that is rich with plants absorbs more water than a lawn. Plants encourage infiltration to restore groundwater and also filter the water.
Preserve Pollinators: Diverse landscapes provide pollen and nectar sources for native bees, butterflies and other pollinators. There are more than 4,000 species of native bees in North America, and their population is declining. Much of that decline is due to the removal of the flowering plants that they evolved to forage from for pollen and nectar.
Native goldenrod and willows are powerhouses when it comes to supporting the widest variety of specialist bee species. The more diversity of native flowering plant species the better, because the more potential there is to support specialist pollinators. Generalist pollinators can get pollen from non-native flowers, but those non-native flowers do not address the needs of the specialists that could really use our help. If you plant for specialists, you’ll help both types of pollinators.
Sequester Carbon: Plants pull carbon out of the air and build their “bodies” out of it, and more importantly, plants’ roots drive carbon into the soil, where it can stay long-term.
Wild bees, including native bumblebees and other solitary bees, are highly efficient pollinators. Unfortunately, many species are threatened due to habitat loss and pesticide use. (Photo credit: Amy Prentice)
Reduce Cement and Lawn
Paved areas do nothing for wildlife, so think about how much cement and asphalt you really need to use your landscape comfortably. Can any be removed and replaced with plants?
Doug encourages homeowners, as a starting point, to cut the area of their property covered in lawn by half. Manicured lawn is attractive to a lot of people, and that’s OK he says. He’s just saying, have less of it. Leave swathes of lawn for paths, and flank those paths with native plants that will make the landscape a more interesting and pleasurable place to spend time.
Remove Invasive Plants
In addition to removing turfgrasses that don’t transfer energy to insects and other wildlife, it’s important to remove invasive plants. They spread aggressively and unchecked because native fauna doesn’t consume them. They also outcompete valuable native plants.
Some invasive plants have been known as weeds for a long time, while others are still sold in nurseries and garden centers.
“Believe it or not, we are still selling plants that are ecological tumors,” Doug says. “They escape from our gardens. … 86% of our invasive woody plants in this country are escapees from our gardens.”
Where Doug lives, in southeastern Pennsylvania, an invasive plant that is exploding is porcelain berry, yet it’s still sold in nurseries. He calls it the “kudzu of the North,” and you may have heard kudzu referred to as “the plant that ate the South.”
“If you have that on your property, get rid of it,” Doug advises.
People try to argue with him that it won’t make a difference, but our individual actions do, in fact, add up.
“East of the Mississippi, 86% of the land is privately owned,” he points out. “If every private landowner managed the invasive species on his or her property, we’d be 86% done. And with the entire country, it’s 83%. If we all got rid of our invasive species, it would reduce the seed rain that constantly falls on those public places. It’s a huge job, but it’s one that every year will get easier and easier and easier.”
Create a 3-Dimensional Space
In human-dominated landscapes, there are tree canopies, and a space full of air all the way to the ground. Dougs says that is not how trees live in nature. In the forest, there are canopy trees, understory trees, a shrub layer and a healthy forest floor with groundcover plants and leaf litter.
In Doug’s county in Pennsylvania, oaks support 511 species of caterpillars. Of that 511, 94% drop to the ground to complete their lifecycle after eating a diet of oak leaves in their larval stage. They dig a hole as a caterpillar to go underground or spin a cocoon in the leaf litter under the tree.
“What the land looks like under the tree becomes really important,” he says. “If you have hard pack soil, if you have lawn right up to the base of your tree that you’re mowing all the time, and you get the droughty days of the summer where that becomes like concrete, it’s impossible for those caterpillars to bore into the soil and complete their life cycle.”
In nature, underneath the canopy of a tree are understory plants, shrubs and groundcovers. Bare ground or lawn up to the tree trunk is not conducive to supporting wildlife. (photo: Courtesy of Doug Tallamy)
Entomophobia
“Homeowners use more insecticide per acre than agriculture, and almost all of it — there are a few exceptions, but almost all of it — is absolutely unnecessary,” Doug says.
He understands why homeowners engage in termite control or why they would treat an outbreak of an invasive species such as spongy moths that threaten native trees. But all the other uses of insecticide are just unnecessary.
“It’s from entomophobia,” he says. That’s the fear of insects.
Every spring, the advertisem*nts come, saying “Call me and I will come spray your entire yard.”
“It means you are living in an envelope of poisons all the time, just so that you don’t have to look at an insect, and that’s not a very good reason,” Doug says.
The greater oak dagger moth specializes on oak trees and, in turn, is an important food source for other wildlife. (photo: Courtesy of Doug Tallamy)
Why Fertilizer Poses an Environmental Problem
In the summertime, green lawns don’t want to be green. But they are forced to stay green by applications of fertilizer and constant watering. Homeowners use water that most areas of the country can’t afford, and that water carries fertilizer into streams and rivers, leading to algal blooms and dead zones in lakes and bays.
“And this is all because we like it to look green,” Doug says. “Again, I understand the value of beauty. I love beauty as much as anybody else, but there are grumpy faces and smiley faces associated with everything we do. And the grumpy faces associated with fertilizing and watering your lawn far outweigh the smiley faces.”
For homeowners living in a community controlled by a homeowners association, rules may mandate keeping a lawn cut and green. But Doug notes that HOAs are run by people, and homeowners interested in making positive changes for the environment can join HOA boards to change the rules.
When a threshold is reached where enough people are doing it, it will change the culture, and then other people who aren’t interested in the goal, but are very interested in keeping up with the Joneses, will start to follow along, Doug believes. “That’s what happens with these cultural shifts. You do it just because your neighbor’s doing it,” he says. “We haven’t reached that threshold yet, but we’re approaching it.”
Fertilizer is carried by stormwater runoff into waterbodies, leading to algal blooms.
Rebecca McMackin
For 11 years, Rebecca was the director of horticulture at Brooklyn Bridge Park, an 85-acre New York City public park built on piers that were originally constructed to accommodate cargo ships. She is also a garden designer and Brooklyn Botanic Garden instructor. She holds master’s degrees in both environmental biology and landscape design. Rebecca encourages inviting biology into the garden rather than trying to keep it out.
She left Brooklyn Bridge Park when she was selected to be a 2023 Loeb Fellow at the Harvard Graduate School of Design. She recently delivered a TED Talk on ecological horticulture and the reasons to let your garden grow wild.
Rebecca was a guest on the podcast in 2021, and we had so much to discuss, our conversation became a two-part episode on Brooklyn Bridge Park and ecological horticulture.
Ecological horticulture is more than the classical organic gardening movement. It looks beyond the flowers and the plants. “It prioritizes the dynamics among the plants and the wildlife and the soil microorganisms and the people critically,” Rebecca says. “People are a big part of this process as well. It’s about these relationships among all of the various organisms, and we consider the garden as a system that changes and adapts to conditions over time.”
Rebecca will join the summit to enlighten us on the importance of creating sustainable habitats for plants, insects, and wildlife.
Rebecca McMackin was the director of horticulture at Brooklyn Bridge Park an is a self-described “ecologically obsessed” horticulturist and garden designer. She was a 2023 Loeb Fellow at the Harvard Graduate School of Design and recently delivered a TED Talk on ecological horticulture.
(Photo Courtesy of Rebecca McMackin)
Mary Phillips
Mary has been with the National Wildlife Federation, the United States’ largest private nonprofit conservation education and advocacy organization, since 2014. She’s always had a passion for wildlife, wildflowers and native plants. As a child, she would go out with her Instamatic camera and take photos of wildlife interacting with plants. She now manages NWF’s Garden for Wildlife program, which has been around since 1973, when it started with the founding of the Certified Wildlife Habitat initiative.
Mary joined me on the podcast two years ago to share how gardeners can access the right native plants.
“About 2 million acres a year are wiped out by development — by us,” Mary says. But, she adds, we have the data and the research that proves we can create pollinator hotspots within communities that will give back some of that lost habitat — food, water and cover — for these essential plants.
NWF celebrated the 50th anniversary of the Certified Wildlife Habitat effort in 2023. It started because of two amazing U.S. Forest Service researchers, Richard DeGraaf and Jack Ward Thomas, who had been studying all the elements of habitat — food, water, cover, places to raise young, etc. — in public lands and restoration areas.
The researchers asked: If you replicated those same features in a small, urban or suburban landscape, could you support wildlife? The answer was yes, you can.
Mary joins the summit to share the wisdom of five decades of how individuals, just like you, have made a difference in ecologically sound practices across more than 300,000 Certified Wildlife Habitats.
Mary Phillips manages the National Wildlife Federation’s Garden for Wildlife program. (Courtesy of National Wildlife Federation)
Emily May
Emily is a pollinator conservation specialist with the Xerces Society. She holds a master’s in entomology from Michigan State and a bachelor’s in biology and environmental studies from Middlebury College in Vermont. She has studied pollinator habitat restoration, bee nesting habits and the effects of pest management practices on native bee communities.
She joined the Xerces Society in 2015 and has focused on supporting crop pollinators through habitat creation and protecting bees and other beneficial insects from pesticides.
The Xerces Society for Invertebrate Conservation was founded by butterfly scientists in 1971, named for the extinct xerces blue butterfly (Glaucopsyche xerces), the first butterfly known to go extinct in North America due to human activities. The society was started to conserve butterflies across the United States and Canada, and now works across all different kinds of invertebrates, from freshwater mussels to at-risk stoneflies. A large team within the society concentrates on pollinator conservation by putting habitat in the ground and working with farmers to conserve pollinators on working land.
“I work on the pesticide reduction team supporting all of that work, making sure that we are doing our due diligence to understand the threat of pesticides to all of these different invertebrates, and doing our best to protect and conserve that wildlife that we’re working towards,” Emily says.
You can learn more about Emily’s work by checking out her videos on the Xerces Society YouTube channel, which is full of good information.
Emily was my guest on the podcast in February to discuss how pesticide regulations fail pollinators. At the summit, she will talk about some of the key pesticide concerns you might face in your garden and provide actionable steps to make your garden more resilient to pest pressure.
Emily May is a pollinator conservation specialist at the Xerces Society.
I hope you enjoyed hearing about the principles of ecological gardening and the Ecological Gardening Summit. If you haven’t listened yet, you can do so now by clicking the Play button on the green bar near the top of this post.
What were your “aha” moments and lessons learned in 2023? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
Episode 012: Beneficial Garden Insects – Bringing Nature Home with Doug Tallamy
Episode 134: Bird Population Decline and What Gardeners Can Do to Help
Episode 142: Why Our Plant Choices Matter: Nature’s Best Hope, with Doug Tallamy
Episode 152: The Native Plant Trust: Why Plant Choices Matter
Episode 206: Our Most Essential Trees: The Nature of Oaks, with Doug Tallamy
Episode 232: Ecological Horticulture at Brooklyn Bridge Park, with Rebecca McMackin, Part I
Episode 233: Ecological Horticulture at Brooklyn Bridge Park, with Rebecca McMackin, Part II
Episode 331: The Ecological Garden Blueprint: 10 Essential Steps That Matter Most
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course. The course is designed to be a comprehensive guide to starting, growing, nurturing and harvesting your favorite vegetables, no matter what you love to eat, no matter where you live, no matter your level of gardening experience.
joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier.
joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
Earthbound Expeditions: Discover South Africa with Joe Lamp’l
GGW Episode 1008: Bringing Nature Home
“The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees” by Douglas W. Tallamy
“Nature’s Best Hope: A New Approach to Conservation That Starts in Your Yard” by Douglas W. Tallamy
“Bringing Nature Home: How You Can Sustain Wildlife with Native Plants” by Douglas W. Tallamy
Rebeca McMackin on Instagram: @oroeoboeococoao
Rebeca McMackin on Twitter: @McmackinRebecca
Let Your Garden Grow Wild | Rebecca McMackin | TED
Certified Wildlife Habitat – Get certified
Xerces Society: Pollinator Conservation Resource Center
“Four Key Gaps in Pesticide Regulation for Protecting Pollinators” by Emily May | Xerces Society
“Organic Pesticides: Minimizing Risks to Pollinators and Beneficial Insects” by Emily May, Aimee Code, Mace Vaughan and Sara Morris | Xerces Society
Proven Winners ColorChoice – Our podcast episode sponsor and Brand Partner of joegardener.com
Earth’s Ally – Our podcast episode sponsor and Brand Partner of joegardener.com
Greenhouse Megastore – Our podcast episode sponsor and Brand Partner of joegardener.com – Enter code JG10 for 10% off your first order
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast was based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Corona Tools, Milorganite, Soil3, Greenhouse Megastore, Territorial Seed Company, Earth’s Ally, Proven Winners ColorChoice and Dramm. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.
