12 minute read
How Your Garden Supports All Life on Earth: A Q&A with Doug Tallamy, Ph.D.
By Keith Nevison, Director of Horticulture and Operations
"It’s where we live, it’s where we work, it’s where we play,” explains Doug Tallamy, Ph.D. This is also a common refrain heard around Santa Barbara Botanic Garden when discussing where we can make an impact. Native plants can reclaim any space, anywhere as biodiverse habitat. This is the message Doug is spreading and one of the reasons we are delighted to be recognizing him with the 2026 John C. Pritzlaff Conservation Award.
Doug will join us at the Garden for the 13th annual Santa Barbara Botanic Garden Conservation Symposium in January, but I got a head start on highlighting his amazing work in a recent interview. During our hour-long discussion, I had the honor of talking with him about his childhood interest in the natural world, steps that we can all take to protect wildlife and enhance habitats, his nonprofit program Homegrown National Park, and much more.
Keith:
Hi Doug and thank you for taking this interview. It’s great to see you again! I read that you became a young conservationist when you discovered pollywogs in a pond by your house, but the pond ended up being filled in when they started building new houses. Can you tell us more about the young Doug?
Doug:
That was a transformational event in my life. It was a little pond in the lot right next to us that wasn’t developed. I visited pretty much every day to watch what was happening for a year. I watched the male toads come and sing and then the females come and the males “hugged” them and then they laid eggs and pollywogs developed. It was my first intense interaction with nature — I was enjoying watching little toads come out by the hundreds, and then a bulldozer came and buried the whole pond, including all the little toads. And what’s interesting to me, looking back on that, is that my reaction was the same as everybody else’s: “We’ve got to save parts of nature that are not already destroyed.” And of course, we do need to do that, but also we can put back an awful lot of what we have destroyed. I could have gone over to my backyard and dug another pond.
My parents probably would have helped me. The shift from conservation to restoration didn’t occur to me, and it didn’t for another 40 years. But I was born loving nature, and I spent my entire youth in any kind of natural setting that I could find.
Keith:
You’ve been telling the public about steps that we can all take to promote conservation. With regard to our more arid conditions here in the west, what measures do you recommend people embrace to protect wildlife?
Doug:
You do have arid conditions, but I don’t think the general principles are any different. There are four things every property needs to do. One is to manage the watershed in which it lies, and every property is in a watershed. Two is to support pollinator communities — not for agriculture, but because they’re pollinating 80% of all plants and 90% of all flowering plants. Three is to support a food web. If you don’t support a food web, you don’t have any animals in your local ecosystem. If you don’t have any animals, you don’t have a functioning ecosystem, which means it’s not producing the life support that we humans need. And the fourth and final one is to sequester carbon. One-third of the carbon in the atmosphere now has come from us chopping down trees. So, wherever it’s appropriate, we want to put plants back. Even if it’s too dry to support trees, the meadows and the prairie plants have deep roots; they’re sequestering almost as much carbon as a forest.
Keith:
When presenting the topic of food webs and native plants to kids, how do you adapt to ensure that they understand your takeaway message.
Doug:
One thing we did was to rewrite “Nature’s Best Hope” for middle schoolers. It’s 100% the same content, but it is rewritten in the language of middle school. You’d be surprised how sophisticated young minds are if you don’t load them down with jargon. If you say, “What do you need to save the monarch?,” they will tell you it’s milkweeds (Asclepias spp.). They already know this. That’s host plant specialization. These concepts are not difficult, and I think it scares adults a whole lot more than it scares our kids.
But in terms of getting immediate action, it’s not going to be the kids. It’s going to be their parents and retired baby boomers. They’ve got the money, they’ve got the time, and they’re looking for something to do. They own the property too. They’re the ones who can really address this immediately.
Keith:
What is the most motivating factor to get people engaged with using native plants in their home landscapes?
Doug:
I think a feeling of empowerment. I show them the simple things one person can do and the difference that it makes. That’s the key, because people want to help, but it’s easy to say, “Well, you know, what can one person do to help the earth?” So, in my talks I outline very clearly what one person can do. You can alter your nighttime lighting, you can shrink your lawn, you can fire Mosquito Joe and the barrier sprays they use. You can do a bunch of things to really improve the ecosystem right on your little piece of the earth, and people get excited about that.
Keith:
From all your talks to native plant societies around the U.S., is there something that you’ve learned from those passionate groups?
Doug:
One thing I’m learning is how much they’re doing. I talked to the Native Plant Society of Texas recently. They’ve got wonderful things on their website. There are 600 species of native plants in Texas that are commercially available. Who knew? And they’ve got them all listed and who you can buy them from. These native plants societies are addressing the next steps locally. If you don’t want to garden at all, they are supplying information about who to hire. That’s what has impressed me the most — the fact that they’re supplying expertise about local plants and partners.
Keith:
Here in California, are there particular species that we should focus on and encourage people to plant?
Doug:
Oaks (Quercus spp.) are a number one keystone species in 84% of the counties in which they occur. We’re finishing a paper going into the American Entomological Society journal looking at the power of oaks. We have about 1,100 species of caterpillars recorded on oaks across the country. Dave Wagner, Ph.D. (professor of ecology and evolutionary behavior at University of Connecticut), thinks it’s going to be around 1,300. That means oaks are supporting about 10% of all the Lepidoptera in the country. California lilac (Ceanothus spp.) is a great ornamental that is also great for caterpillars. It’s also great for pollinators. Mountain mahogany (Cercocarpus spp.), that’s another one, very powerful. Buckwheats (Eriogonum spp.) are really important host plants. Finding powerful plants that support the pollinators and caterpillars and are beautiful is key.
Keith:
You’ve had a long career in academic entomology. What spurred you to start researching and presenting on the subject of insect use of native plants and their importance in feeding songbirds and supporting the web of life?
Doug:
In graduate school we studied plant-insect interactions for a long time. The major takeaway was that most insects that eat plants are host-plant specialists. Just the way the monarch (Danaus plexippus) is a specialist on milkweeds, about 90% are specialists. When I got a job at University of Delaware, I started looking at insect behavior, parental care, how cucumber beetles chose their mates, things like that. But then in 2000, my wife and I moved to a farm property in Oxford, Pennsylvania. When we moved in, it was a jungle of invasive plants from Asia. Our goal was to restore this property, but we couldn’t walk through it. I cut trails and I would look for insects. And it occurred to me one day early on, there are no insects on these nonnative plants. I thought this would be a good project for an undergraduate, to measure insect use of native and nonnative plants. In the literature, there was a long list of why invasive plants are a problem but wrecking the food web was not on that list. I said, “Well, gee, this might be a research opportunity.” We got the funding to do a bunch of research, but it was that one day of walking through our property and saying, “Hey, look, the insects are not eating these plants,” that changed the direction of my research. I gave up on how cucumber beetles choose their mates, and I’ve been doing this ever since.
Keith:
You’ve written six books so far, continue to lecture to students, give 200 presentations a year ... you’re doing a lot. On the topic of native plants and the web of life, what are some of the projects you’re currently working on?
Doug:
I think the most important thing that we’ve been doing recently is looking at how we landscape under trees. If we’ve got oaks and other trees making a lot of caterpillars, most of them (like 90% or more) don’t complete their lifespan on the tree. They drop from the tree and they pupate underground, or they pupate in the leaf litter that’s under the tree. However, our horticultural practices don’t allow that leaf litter; we rake it up or we blow it away or we have grass. We have lawn right up to the tree. Grad student Emma Jonas found that caterpillars had a tough time burrowing down through the thatch of grass. They do go down and they do pupate, but it’s right at the surface. What does that mean? It means we walk on them when we mow, and we squish them. We have shown that the pressure from a single footfall is enough to kill 40% of the caterpillars that pupate under a tree, and mowing a lawn kills 50%. So, the object is to create “no-go zones” under trees that are landscaped. This is where we can create healthy ground covers. All the research isn’t done, but if you don’t pupate caterpillars successfully, then you don’t have adults and then you don’t have bird food and on it goes. I know that when it’s really dry that’s tough, and I know you’ve got fire issues, so nobody wants any leaf litter on the ground. So, the challenge in California is to design a landscape under trees that is not a fire hazard but can still promote caterpillar survivorship.
Keith:
Understanding that there are a multitude of issues for the public to feel engaged on, how do we at the Garden continue to elevate our mission to conserve native plants and habitats for the health and well-being of people and the planet?
Doug:
I give a talk and people say, “What is the single most important thing somebody can do?” I say it’s vote. The people we vote for are making huge decisions with huge implications. It’s not trivial. We have more people on this planet than it can support. We’ve got to raise the carrying capacity of the planet by putting the stuff back that creates the carrying capacity, and that’s the plants. Getting that message to everybody who visits the Garden, everybody period, is really, really important. We need air, we need water. We need life support. It doesn’t matter what your political views are. Everybody needs a healthy environment. It’s not just for tree huggers. Every single person absolutely requires healthy ecosystems, because that’s what keeps them alive on the planet.
Keith:
Can you tell us about Homegrown National Park?
Doug:
We’re in a biodiversity crisis: global and national. We’ve lost 22% of our butterflies since 2000. We’ve lost one-third of our bird population in the last 45 years. Even though we have parks and we have preserves and land conservancies, it’s not good enough. What’s between those parks and preserves? It’s our private properties. It’s where we live, it’s where we work, it’s where we play. It’s 135 million acres (54 million hectares) of residential landscapes in the U.S. — a huge opportunity for the private landowner to participate in conservation. Homegrown National Park was designed to tell private landowners that they have that responsibility. It’s a hub where people can get information about their responsibility and do it right where they live to address this biodiversity crisis. It also divides the conservation responsibility up into something that’s doable. Don’t worry about the entire planet; just worry about your piece of that planet. Remove the invasive plants that we use as ornamentals. Put in those keystone plants. We give private property owners a mechanism to become part of this movement, and they register their property on our biodiversity map and the amount of area that they’re actually conserving — you reduce the area of lawn, maybe you planted a tree, maybe put an aster (Family Asteraceae) in a in a flowerpot. This gives us a quantitative measure of our progress toward restoring that 40 million acres (16 million hectares) that’s now lawn. Then your little piece of your county is represented with a firefly emblem. The object is to get the whole map to light up with fireflies so we can see how we’re doing with conservation on private property. It’s free because we’re not trying to pull membership away from other conservation groups. We’re not competing. We want to unite all the conservation groups.
To learn more about how you can join the native plant movement and make a difference in your community and to hear more from Doug, join us on January 31, 2026, for the Garden’s 13th annual Conservation Symposium. Registration is now open for free online access SBBotanicGarden.org/symposium-2026, or you can join us in person and have a chance to meet Doug personally. Also, check out Homegrown National Park at HomegrownNationalPark.org and register your land today.
