Garden as if life depended on it! Doug Tallamy wrote these words in my copy of his book, Bringing Nature Home. No, I’m not a special friend or acquaintance, he wrote similar, if not identical words inside all the books he signed that day. On the other hand, though, I am special. I’m a gardener with extraordinary power … I can choose to plant whatever I want. You are also extraordinary, as you have exactly the same power as I. And if we, as gardeners, do just a little of what Tallamy suggests – increase the number of native plants growing in each of our gardens– we, individually and together, may be able to make a significant difference in the nature of our future.
Professor Tallamy chairs the Department of Entomology and Wildlife Ecology at the University of Delaware in Newark. There he teaches insect taxonomy and ecology courses and researches how insects and plants interact. You can delve into his research simply by searching his name in Google Scholar. You’ll see studies like Squash beetle feeding behavior in the journal Ecology, or Effects of non-native plants on the native insect community of Delaware in Biological Invasions … you get the picture, he’s an insect junkie. But he’s still able to write compelling, and very readable non-scientific explanations of the side-by-side evolution of local insects and local plants that enables them to support not only each other but the many birds and other creatures farther up the food chain … and how non-native plants are simply not as palatable or user-friendly, so to speak, to local insects … and when faced with fewer or no native food, insects either vastly decline or disappear … and when this happens local birds have fewer insects and caterpillars to feed their little bird babies … and weaker or fewer bird babies means fewer birds to feed other creatures farther up the food chain. Ok, any grammar or English teacher reading this is probably cringing at my run-on sentence, but I think I’ve made my, or more correctly Tallamy’s point. Fewer natives = fewer bugs = fewer birds = less food for all.
Time and again Tallamy has found substantially more insect biomass (bird food) surviving on native shrubs, trees, and plants as opposed to alien greenery growing in the same area. One of his students, Meg Ballard, as her master’s thesis, conducted a two-year comparison of insect biomass (bird food) found on six herbaceous natives – eastern black nightshade, black-eyed Susan, devil’s beggarticks, ragweed, horseweed, and goldenrod – and six herbaceous aliens – lambsquarters, cocklebur, velvetleaf, jimsonweed, pigweed, and cosmos. Compared with aliens, the natives produced nearly 6-times more generalist insect herbivore biomass – that’s science-speak for insects that eat just about any plant (generalists) rather than specialize on specific plants and therefore provide a good amount of bird food. This comparison produced no evidence that generalists prefer alien plants, Tallamy writes, or that alien plants produce as much insect biomass (bird food) as native plants.
Some of you are likely thinking, ‘You want me to plant plants that attract more bugs?’ The short answer is yes. More native plants = more native bugs = more bird food. An example is black-eyed Susans. They grow with virtually no work, offer color throughout mid to late summer, and provide food for local birds.
Tallamy’s arguments for planting natives focuses more on trees. Consider oaks (Quercus), the mightiest when it comes to supporting Lepidoptera species (moths and butterflies). Oaks support 534, followed by willows (Salix) and cherry or plums (Prunus) at 456 each, birch (Betula) at 413, poplars/cottonwoods (Populus) at 368, and crabapples (Malus) at 311. Whereas beech (Fagus) support just 126. (Get the book and read the list on page 147.)
Bringing Nature Home includes color photos of native trees, native perennials, and native insects, as well as lists of natives for all regions of the continental U.S. – sorry Alaska, Hawaii, and other island locales – and this alone makes it a valuable reference. It also argues persuasively that gardeners move away from planting only for aesthetics and toward planting more to achieve a balanced food web. Tallamy even cites the success he and his wife have had in converting their own suburban yard from a lawn near-wasteland to a richly diverse insect-laden, bird-friendly, native-plant haven.
Humans have disrupted natural habitats in so many ways and in so many places, and this is increasingly evident in ever decreasing numbers of amphibians, butterflies, birds, and other creatures. But as gardeners and stewards of our land, we are empowered to reverse some of this disruption, simply by planting natives.
I, for one, plan to rise to Tallamy’s challenge by planting more shrubs and perennials native to Connecticut. Check out the links below to learn how you can be so empowered as well.