Book by Douglas W. Tallamy. Review by Janet Allen.
Our Wild Ones mission is to “promote environmentally sound landscaping practices to preserve biodiversity through the preservation, restoration and establishment of native plant communities.” This statement could easily be mistaken as a summary of the main ideas in Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens by Douglas Tallamy. The book validates our Wild Ones principles with sound scientific support. In fact, after reading it, you’ll see that our mission is even more important than we ourselves may have realized – and for reasons that may surprise you.
Native plants and biodiversity
Plants are the foundation of the food web because they capture the sun’s energy and turn it into food. We’re all familiar with the “who eats whom” of this web, but we don’t fully appreciate insects’ indispensable role in it. Tallamy, an entomologist, explains that they’re essential to healthy ecosystems because so many animals depend partially or entirely on them for food. Even nectar-loving hummingbirds feed insects to their young. A land without insects, he says, is a land without higher forms of life.
Of course, all plants – native or not – capture the sun’s energy. Especially interesting for us Wild Ones, though, is that native insects thrive on native plants, but not on most alien plants. (Although many of us are accustomed to using the term “non-native” plants, Tallamy uses the term “alien.”) One study, for example, showed that native plants supported 35 times more caterpillar biomass (amount by weight) than did alien plants. The leaf chemistry of alien plants is the chief reason native insects can’t and don’t eat the leaves of most alien plants.
Now you may be thinking that supporting caterpillars and insects is not exactly what you have in mind when you select plants for your landscape. Even people who garden for wildlife don’t particularly want them to eat the plants, with the possible exception of our beloved butterflies’ larval host plants. In fact, one reason for the popularity of many commonly sold aliens is that most insects do not eat them, and so it’s easy to maintain the conventional gardening ideal of perfect, non-chewed leaves.
Those of us whose native landscapes have matured a bit, though, may not quite recognize the picture being painted. After all, our landscapes include mostly or exclusively native plants, but we don’t see an ugly mess of chewed leaves. That’s the good news. As Tallamy points out, a natural landscape is in balance. If you look closely at healthy woodlands or grasslands, you can spot occasional nibbles that signal their support of insect populations, but the overall landscape is beautiful. And so are the native-plant communities of our home landscapes.
Dr. Tallamy states three simple truths about biodiversity. First, the creatures we enjoy won’t be here if we take away their food and places to live. Second, in many parts of the country, the only place left for wildlife is in our own yards. Finally, our home landscapes are increasingly planted with alien plants insects are unable to eat, thus impoverishing the food web. The inevitable conclusion is that gardening with native plants must become mainstream if we are to preserve the plants and animals that delight us and create the ecosystems we depend on.
In addition to explaining why native plants are important to biodiversity, Tallamy provides real answers to awkward questions people frequently ask Wild Ones. One of the most common is, “Why can’t we declare ‘alien plant X’ to be native? After all, it’s been growing in North America for hundreds of years.”
Tallamy explains the essential problem with this complaint: It doesn’t consider the role plants play in the ecosystem. Alien plants occupy space and use resources that would otherwise be available for native plants, but the sun’s energy they harness isn’t passed to the rest of the food web since insects don’t eat them. Plants that cannot function as part of the ecosystem cannot be considered to have “become native.” For me, this is a compelling argument.
The alien plant, phragmites, perfectly illustrates this concept. Research shows that phragmites supports 34 times more insect species in its native European homeland than it does in North America
– even after living on this continent for hundreds of years.
A chapter on “The Costs of Using Alien Ornamentals” discusses additional problems with alien plants. One risk is that insects or disease can be brought to this continent by importing alien plants. Chestnut blight, imported on alien plants, has had particularly devastating consequences for biodiversity in North America. And it’s not easy to predict which alien will become invasive – sometimes, they “behave” for decades before exploding into our natural areas.
This isn’t a run-of-the-mill gardening or landscaping book, but it does provide practical advice in the chapters “Creating Balanced Communities,” “Blending In with the Neighbors,” and “Making It Happen.” Unlike most other garden books you’ve read, one chapter explores “Gardening for Insect Diversity.”
Tallamy helps us develop an appreciation for insects by sharing his knowledge and enthusiasm in “What Does Bird Food Look Like?” He also describes some good plant choices in “What Should I Plant?” since not all native plants provide equally well for wildlife.
One of the handiest chapters is “Answers to Tough Questions.” He provides convincing, science-based answers to questions your non-Wild Ones friends may have asked you, or that you may have wondered about yourself.
Useful appendices include “Native Plants with Wildlife Value and Desirable Landscaping Attributes,” which lists plants for each region of the country, and another which lists “Host Plants of Butterflies and Showy Moths.”
This book is enjoyable to read since Tallamy’s enthusiasm for gardening, for plants, and for wildlife – yes, especially insects – comes through. One tip for readers, though, is to take in stride the occasional science jargon you’ll encounter. Get out the dictionary if you’re particular about such things, or simply read beyond the technical terms (as I did). I found the research citations in the body of the text to be distracting in a book whose intended audience is the gardening public, not scientists. This wasn’t a barrier to understanding, however, just an annoyance. The main ideas are clear and easy to understand.
I rank this as the most important environmental gardening book I’ve read. It’s about ecology and about gardening, but it’s more than that. It’s inspiring and sobering. As Tallamy says, “For the first time in its history, gardening has taken on a role that transcends the needs of the gardener.” His central message is that restoring native plants to our yards is the key to the future of biodiversity in the United States, and it’s urgent that we accelerate our efforts.
He issues a call to action in the afterword titled “The Last Refuge”: For the past century we have created our gardens with one thing in mind: aesthetics. We have selected plants for landscaping based only on their beauty and their fit within our artistic designs. Yet if we designed our buildings the way we design our gardens, with only aesthetics in mind, they would fall down.
Our success is up to each one of us individually. We can each make a measurable difference almost immediately by planting a native nearby. As gardeners and stewards of our land, we have never been so empowered – and the ecological stakes have never been so high.
We Wild Ones can make a difference even beyond our own yards. With the knowledge we gain from Bringing Nature Home, we can help Americans shift away from alien ornamentals to native plants – a shift that will preserve the plants and wildlife so important to a healthy, joyful world.
Janet Allen, charter President of Habitat Gardening in Central New York (NY) Chapter, and a member of the Wild Ones National Board, serves as Member Certification Committee Chair.
March/April 2008 Wild Ones Journal.