Why Natives?

So, what's the big deal about native plants?

As it turns out, the answer to that question is, at first glance, rather strange: native plants are important because insects are able to eat their leaves. It's only by looking at that statement in the context of the entire food web that we can understand how meaningful that is.

Let's start with the sun's energy. Green plants are able to harness the energy from the sun, through photosynthesis, and turn it into food energy for animals - that happens when animals eat the plants themselves, or eat the animals that have eaten the plants. Without plants' ability to harness this energy, life on earth, as we know it, wouldn't be possible.

But, many animals can't derive their energy from eating plants themselves, so they depend on the middlemen. Think of grass, cows, and humans, for one example close to home. Our world is full of grass - if only we could eat it directly! But we can't digest it, unfortunately. Enter the cow. Grass is her food of choice. She is adapted to eat it from thousands of years of co-evolution. Then, we can eat the cows, who have handily converted the energy harnessed by the grass into a form we can use. Thank you, Bess!

Back to what this has to do with native plants. Insects are the great middlemen of life on earth. They are well-adapted to eating leaves and converting that energy into their own bodies; their own bodies then provide a crucial food source for so many animal species which cannot eat the plants themselves, but which will happily eat the insects, or the animals that eat the insects. And, as it turns out, insects prefer to eat the leaves of plants they have grown up with - over tens of thousands of years, that is. Moreover, many insects specialize in eating the leaves of just a few plant species. If those plant species aren't around, the insects aren't around, either - their populations drop, or disappear entirely. And if insects are the middlemen to the rest of the food web above them, that spells disaster for the rest of the food web.

Case in point: butterflies. Here's a well-known example - monarch butterflies can only reproduce on milkweeds (Asclepias spp.). The butterflies may like to drink the nectar from many different flowers, but when the crucial moment comes to lay eggs, if there's not a milkweek around, there is no next generation of monarchs. The monarch caterpillars need to eat the leaves of milkweed to grow and turn into butterflies themselves. Most other butterfly caterpillars find themselves in similar situations, able only to eat and reproduce on the leaves of a specific set of plants - all plants they have shared a co-evolutionary relationship with.

Second case in point: birds. Yes, adult birds do eat berries. But baby birds eat insects. When their parents can't find enough insects to feed their babies, bird populations decrease. And that's exactly what's happened over the last 50 years.

It's not hard to see where this is going. Gardening is subject to the same whims and fancies as the clothing industry - things go in and out of fashion, and everyone wants the newest thing, the thing that nobody else has, and then a trend is born and everybody else wants that thing, too. The problem is, most of those new things in gardening have been the exotic plants imported from China and Japan, Europe, and other parts of the world. Exotics make up an amazing proportion of our typical landscape plants. That privet hedge, that Bradford pear tree, the pretty rose-colored barberry, those striking fountain grasses, the dwarf spireas...all non-native. Given that scenario, where is the food for the insects, the insects which play such an important role in sustaining all other wildlife?

All of the above information is detailed in Dr. Douglas Tallamy's book, Bringing Nature Home (Timber Press, 2007). It is an outgrowth of his own research, and the research of many others throughout the years. Read a longer review here on our website.

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