- [Male Announcer] Growing a Greener World is made possible in part by: - [Female Announcer]: so you can roam the Earth with a lighter footprint.

- [Male Announcer] And the following: [gentle instrumental music] - [voice-over] I'm Joe Lamp'l.

When I created Growing a Greener World, I had one goal.

To tell stories of everyday people.

Innovators, entrepreneurs, forward-thinking leaders who are all, in ways both big and small, dedicated to organic gardening and farming, lightening our footprint, conserving vital resources, protecting natural habitats, making a tangible difference for us all.

They're real, they're passionate, they're all around us.

They're the game changers who are literally growing a greener world and inspiring the rest of us to do the same.

Growing a Greener World.

It's more than a movement, it's our mission.

[dramatic music] Every once in awhile, we encounter a concept so intuitive that we never really give any thought on how to articulate it.

A good example is all the wild creatures we enjoy in and around our yards and gardens.

They're just there, right?

Naturally.

But stop and think about what would happen if you took away their food sources and the places they live.

Well, guess what, those animals we take for granted as just being a part of our world suddenly won't be there tomorrow and that's exactly what's happening all across America and beyond.

Part of the problem is urban sprawl and habitat destruction and too many areas of the country, there's no place left for wildlife but in the landscapes and gardens, we, ourselves, create.

Have you ever stopped to consider that all the food for all the animals on this planet starts with energy harnessed by plants.

So, choosing the right kinds of plants in our gardens is playing a bigger and more important role than ever in sustaining directly or indirectly all the animals with which we see our living spaces.

But we add to the problem when we replace too many of our native plants, plants that have adapted to our surroundings over millions of years with exotic specimens and new varieties sometimes called alien plants that are chosen more for aesthetics and maintenance reasons than for the role they play in the local landscape.

Our love affair with non-native plants that had been purposely introduced into our surroundings threatens that delicate relationship.

It's taking a significant tool on the animals, especially insects, that we depend on in our own ecosystems and that has to change.

When it comes to understanding the critical relationships between native plants and the creatures that depend on them, Doug Tallamy is right at the top.

He's an award winning author on the subject and professor at the University of Delaware where he's also Chair of the Department of Entomology and Wildlife Ecology.

His passion?

To better understand all the ways insects interact with plants and how those interactions determine the diversity of larger animal communities.

- So, I went to Graduate School in Entomology, became an entomologist, fascinated with insects, and part of my graduate training was to learn about plant insect interactions, how plants and insects interact.

This is a huge field because there are a lot of plants and a lot of insects and how they interact depends on what is happening in the rest of the food web and the major theme from all of those years of studying was that most insects are host plant specialists.

They adapt to the chemical defenses of particular plants.

[soft music] - [Joe] But all of Doug's theoretical academic research was about to really come home.

Literally in a very concrete way.

- But in 2000, my wife and I moved into this property here in Oxford, Pennsylvania.

it was overrun with non-native plants.

We decided we would restore it to its some former state of nativeness and in the process of doing that I noticed well, our local insects are not eating Oriental Bittersweet and Autumn Olive and Japanese Honeysuckle and Bush Honeysuckle and I said well, no surprise there, they did not co-evolve together as we learned in graduate school.

Now, nobody was talking about non-native plants back then, the term invasive species didn't exist, even though they were here, we weren't talking about them.

- [Joe] The terms invasive, alien, non-native, and native plants are common today but they were rarely mentioned even just a generation ago.

So, perhaps, it's no surprise that there's still a bit of confusion and disagreement about what they actually mean.

- Some people think well, if it's from North America, it is native and they'll gather plants all over North America and put them in their garden but what they've really done is create a North American plant zoo.

A native plant, by my definition, is one that has evolved within the context of the local food web.

Now, food webs can be large but, for example, if we take blue spruce form the Rocky Mountains and plant it in Delaware, it is a long way from the ecosystem within which it evolved and also the creatures that it evolved with, so, organisms in Delaware have never seen a blue spruce before and even though the plant is from North America, it is not from a Delaware ecosystem.

So, I like to think of native plants as plants that are from within local food webs that have an evolutionary history with the other plants and insects and organisms within that food web.

- [Joe] Doug's not the only one working on the subject of bringing nature home.

Thankfully, there are other key influencers scattered around the world, helping to promote the message of creating healthy, living landscapes with a focus on indigenous plants.

In fact, Rick Darke wrote the book on it along with contributions from his friend and colleague, Doug Tallamy.

While these two share a zeal for creating and protecting ecologically balanced landscapes, their approaches are quite different.

Rick's rise to horticultural prominence started with a college botany course.

His studies led to a 20 year career at Longwood Gardens, considered one of America's most important botanic gardens.

When he left, he was curator of plants with a responsibility for over 11,000 plants in Longwood's collection.

Today, Rick heads his Pennsylvania-based consulting firm focused on the design and management of living landscapes of diverse projects all around the world.

But it's back home where Rick, along with his wife and co-horticulturalist Melinda Zoehrer get to enjoy their own living landscape that is as biologically balanced as it is beautiful.

- So often people say, it's native if it was here before a certain time and a certain place or before certain other people arrived.

So, they're talking about a plant and a place and a time but it doesn't really say anything about relationships.

We know that what really matters is not just the plant being in a place for a time but what essential relationships have evolved during its time there.

So, it's a plant, it's a place, it's a time, and it's long evolved essential relationships.

- In their own unique styles, both Rick and Doug's award winning books take on the topics of what we can and should do to bring more life to our own home landscapes and why that's so important.

Your book, Bringing Nature Home, first of all, I have to tell ya, I love that title but I also think that it probably raises a question to people that may hear that and go, well, you know, especially the Suburbanites going, well, bringing nature home, I already have nature all around me, I see it everywhere, but they probably really don't, do they?

- Yeah, we have eliminated so much nature so fast that most people don't realize how little is left.

And it's deceiving.

You drive down the road, both sides of the road are wooded, you picture that going forever.

It doesn't.

It goes about 20 feet and then it's some development.

So, we've, particularly in the east, we have devastated our natural areas to the point where if we're going to have functioning ecosystems, if we're going to have biodiversity, we need to start sharing the property that we've taken.

- [Joe] With ever-shrinking natural habitats outside of our control, it's now more important than ever to make more room in our own home landscapes for the plants and trees that our native wildlife depend on.

- The population in the US is growing constantly.

I just read this morning, actually, about the US is gonna be the fastest growing developed nation in the world shortly.

We now have 320 million people.

And if you look around, we really are pretty much everywhere either in our cities, our suburbs, our exurban habitats which are highly developed or our agriculture.

Only 5% of the US is considered relatively pristine.

So, we have to pay attention to the way we landscape all of those areas.

So, I'm encouraging people to think about the percentage of native plants that they have in the yards, the ones that are really productive in supporting life.

And you don't have to count species, think about the bio-mash.

If you think you have one huge oak in your yard, you are doing a great service to your local ecosystem.

Does that mean you can't have any non-natives?

No, it doesn't mean that.

You can have a crepe myrtle as a focal point in your yard with a beautiful blooms.

But when you look around your neighborhood and 80% of the plants are crepe myrtles or Bradford pears or burning bushes and that's pretty much what it is when we measure it, about 80% of our woody ornamentals are non-native.

- [Rick] I often say that gardens are the ultimate balancing act.

If you look around this garden that we're in, it is mostly eastern regional indigenous plants, call them natives if you want, but there are many exotics in here.

- [Joe] While it's one thing to host exotic plants in your landscape, a common concern is if those exotic or alien plants become invasive.

- There's genuine concern about the potential detriments of an overuse of alien ornamentals or alien plants of any sort, really.

The most obvious is that you use a plant that goes beyond a garden and establish itself in a place where it takes up space that would normally have been occupied by some other plant with deep connective relationships in that local ecology and this is business of escape and it's very real.

- 85% of our woody invasive plants are actually escapees from our garden and we continue to go on plant explorations, sell them in our nurseries, exacerbating the problem.

By invasive I mean they have now left our gardens, they're penetrating the natural areas throughout the country to a point where a third of the vegetation in our natural areas is non-native.

So, that's one issue.

Another issue is that the plants we put in our local landscapes have become the first trophic level.

Those are the plants that are driving food webs and if those plants are from Asia and Asian plants are poor at driving food webs, what are the consequences to other things that need to live in our neighborhoods?

Now, in the past we've thought, you know, humans are here, nature's some place else, and we can do what we want without any consequences and in the past, that largely worked because there weren't that many humans.

Today, though, we're pretty much everywhere.

We're either agriculture or we're our shopping malls, our suburbs, our cities, and if we landscape those areas with plants that are not supporting food webs or supporting them very poorly, we're going to seriously impact other creatures in our ecosystems.

Why does that matter?

Because it is the diversity of life and ecosystems that runs those ecosystems.

As you increase the number of species in ecosystems, ecosystem function goes up.

If you decrease it, the ecosystem function goes down.

Why do we need ecosystem function?

Because ecosystems create the ecosystem services that support humans.

So, all of this is tied together, we can be selfish about it, we need to preserve other species right where we live for our own good.

- [Joe] While the term ecosystem function can sound a bit intimidating, think of it in terms of this simple yet important things that allow nature to function as it was intended.

For an entomologist like Doug, it always comes back to the bugs.

You and I share an admiration for a special author, E. O. Wilson, and he has a quote in your book about bugs and he says they're the little things that run the world.

- That is so true because they are crucial to almost every aspect of terrestrial ecosystem function.

They recycle nutrients, they pollinate our plants which then sequester carbon, they're essential to food webs.

If we were to eliminate insects from the earth according to E.O, humans would last about two months.

So, and we can do that experiment and see what happens but I'd rather not.

- I'm with you.

A much less drastic experiment that Doug tried drives home just how critical it is to the entire ecosystem to have lots of native plants to attract large insect populations.

- I did a fun little experiment last summer and this actually is something you can do at home where I simply counted caterpillars on July 25th and July 26th on a white oak in my yard, a black cherry in my yard, I moved to my neighbor's yard and counted them on Bradford pears and on burning bush.

I counted the same amount of, or measured the same amount of vegetation and only look at the caterpillars at head height.

On the white oak, I found 410 caterpillars from 19 different species.

On the black cherry, I found 256 caterpillars from 12 different species.

On the Bradford pear, I found one caterpillar from one species and on the burning bush I found four caterpillars from one species and they were tiny little leaf biters that are too small for a bird to eat.

Why were there not more caterpillars on Bradford pear or burning bush?

Because there are chemical defenses in those plants that our local insects have not adapted to.

Insects in China can eat callery pear, that's what Bradford pear is, and burning bush, a species of Euonymus because they have been exposed to those chemicals for eons but now that they're over here, they've only been over here what?

100 years?

It's nothing in evolutionary time and our insects have not been able to adapt to those plants.

Our insects can eat the oak and the black cherry because they have been in these ecosystems for actually millions of years and the insects have adapted to them.

Very productive plants.

Now, in the past, one of the reasons we chose Bradford pear and burning bush and all these other plants was the fact that they were pest-free, they had nothing eating them, it was a criteria we looked for.

And if we're growing our plants strictly as decorations, that becomes an important trait.

But plants are more than decorations, they're essential components of our local ecosystems, so we now have to think about how a plant looks as well as, we have to think about how it acts, what does it do, what does it function, as well as what does it look like.

Most people would not object to having a beautiful oak tree in their yard.

An important point when I did that 410 caterpillar study, I then stood back from that oak tree, took a picture, and there was no damage that you could see, you couldn't see one of those caterpillars and unless a homeowner went up and carefully inspected the leaves, never would've known there were caterpillars on there, so, a plant, a tree, can support a lot of life without being defoliated.

So, again, if I'm a foraging bird, looking for a meal that day, I would not be going to burning bush or Bradford pear, I'd be on that white oak and the black cherry.

So, the plants you put in your yard have a tremendous impact on local food webs.

- [Joe] And yet we continue to fill our yards and landscapes with plants and trees that have little to do with promoting those vital relationships between them and wildlife.

So, what are the hurdles then?

Because we still tend to gravitate towards those alien ornamentals because we like that beauty and we like the fact that those plants are pest-free but that's not really what we need.

We need to adopt more of a philosophy of embracing the natives.

How are we gonna do that?

- We need to educate people that this is necessary, that a typical homeowners property is an important component of the local ecosystem, they can't opt out of ecosystem function anymore, they have to participate, and the way to participate is to bring those functional plants back to the landscape.

Once that message is delivered, I have found that people are very receptive and they're eager to take part in what is a huge conservation movement.

- Kind of important.

- Very important.

[soft music] - [Joe] So, what brings life to a landscape in a way that not only promotes more vibrant wildlife habitat but also satisfies the desires of the people living there?

While plants will always be at the heart of any garden or landscape, Rick spends a lot of time studying this very topic.

He suggests that rather than beginning with a set of objects, we start with a set of goals to ensure the landscapes we live in are beautifully layered, biologically diverse, and broadly functional, and the key to that is a focus on building layers with a simple, logical process.

- It begins with simply looking around your landscaping taking inventory, look at your landscape, do you have a canopy?

What does the ground layer look like?

Is it mulch or is it a richly organic accumulation in which all kinds of things live?

Do you have an understory?

Do you have a shrub layer?

We are so often taught to approach gardens in terms of what plants you have, not what layers do you have, that we take an object or the person or the landscape instead of a relationship orienting pproach and getting back to layers means you will be thinking about relationships.

It's important to bring layers back into the garden because there's so many things that depend upon special nature of different layers.

They are layer specialists.

There are animals and plants that really only live in the ground layer, there are others that really live in the mid story, there are others that are only canopy dwellers.

If you don't have these different things, you just simply cut out the opportunity for a lot of these things to live.

- [Joe] Leave it to Rick's colleague, Doug, and his insatiable quest for understanding ecosystem function to identify a key missing link in the modern landscape.

- When Doug was starting to look at relationships and where they exist and he was looking at how many relationships were just appearing from a lot of our common ground, you go out and what you thought was the wild or nature and in fact, the layers were gone and there was not that much living there.

And so, he was thinking, where can we find a new place for that to happen?

And if you look at the extent of the suburbs and you just said okay, if each person who has their suburban plot, if they think of themselves as living in a little bit of this new nature, they can reprise the layers, they can bring that richness back, and it really can be a new definition of nature.

So, really, the suburbs and our collective gardens become the new nature.

- [Joe] So, as you design or modify your landscape to be a part of the new nature, think in terms of how you're building it in layers.

Working from the top down, the tallest layer is always the canopy.

While you don't often notice them from their showiness and flower, the autumn color of deciduous canopy trees is unsurpassed.

Moreover, it's their sheer massive wood and volume that provides sustenance, hunting, and resting perches and nesting cavities for an abundance of birds, mammals, insects, and other invertebrates.

Beneath the canopy, resides a multitude of smaller trees referred to as the understory tree layer.

While this layer offers so many choices in size, shape, color, flower, and form, the aesthetic value to us is vast as are the benefits to a lot of wildlife.

Understory trees offer ideal density, height, food sources through flower, fruit, and seeds and branching structure through shelter and nesting.

These features and more make understory trees the only good option for many species where canopy trees are too high.

Heading back down closer to earth, the shrub layer occupies space beneath the understory trees.

While offering many of the same benefits, height, density, and food sources make these critical plants for attracting a diverse range of insects and other wild life.

In addition, it's perhaps the most versatile layer for design functionality in the landscape.

The herbaceous layer is the lowest of the above ground layers.

It also has the greatest botanical diversity of all above ground layers simply because there are more species of these than of all woody plants and the more diverse layer offers more shelter and cover for wildlife.

An important added benefit is an overlapping sequence of blooms through the seasons leading to a succession of ripening fruits and seeds, a staple food source for countless creatures.

Finally, we have the ground layer.

For most residential landscapes, the ground layer of choice is mowed turf.

While it serves a purpose in the landscape, it's function and ecological biodiversity is slim.

In fact, mowed turf offers little to the cover, shelter, and sustenance necessary to sustain wildlife.

And lastly, no yard or garden is too small to play a role in the bigger picture.

- Many people are concerned that the piece of property they owned in actually too small to make a difference.

Say, I only own a third of an acre and I can do whatever I do and it's not going to help biodiversity.

You know, it's true.

The bigger the property, the more effective it will be but your third of an acre is connected to your neighbor's and that's all of a sudden two thirds of an acre which is connected to another neighbor and even if you are a little island, you're important in a number of respects.

Many of these organisms move around a lot, butterflies, for example, our friend the monarch is migrating all the way to Mexico.

It needs stopover points on the way.

And birds migrate.

Many of our breeding birds breed in Canada and they've gotta move through our suburban and city neighborhoods to get to those spots and they have to stop along the way and eat.

So, if you have a choice between an oak tree or a Ginkgo as the single tree that can fit in your yard, the oak will support migrating birds during stopover, the Ginkgo will not.

So, your little piece of the world actually can make a big difference even if your neighbors don't participate.

But talk to them so they will.

- While it might seem a bit scary to think that a lot of the habitat that our native wildlife depends on for survival is rapidly going away, we can take an active role in taking some of that back starting right in our own yards and balconies.

Bringing nature home really does define our gardens as the new nature and if you'd like more information, we have helpful links on what you could do on our website under the show notes for this episode, the website address, it's the same as our show name, it's GrowingAGreenerWorld.com.

Thanks for joining us everybody, I'm Joe Lamp'l and we'll see you back here next time for more Growing a Greener World.

♪ - [Male Announcer] Growing a Greener World is made possible in part by: - [Female Announcer]: so you can roam the Earth with a lighter footprint.

- [Male Announcer] And the following: [ambient electronic music] ♪ [male announcer]: Continue the garden learning from the program you just watched, Growing a Greener World.

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