Blue Ridge Naturalist: Non-native Plants Can Be Remarkably Nature-friendly, Part One


© Marlene A. Condon

When home construction destroys the soil profile, it’s difficult for native plants to take root. (Photo credit: Marlene A. Condon)
When home construction destroys the soil profile, it’s difficult for native plants to take root. (Photo credit: Marlene A. Condon)

Many people have taken to heart the words of Doug Tallamy (the entomologist who wrote Bringing Nature Home) to grow native plants because many native leaf-eating insects depend upon them.

They’ve also been moved by his statement that “aggressive plant species from other continents…were rapidly replacing what native plants” were on the rural property he and his wife had purchased. Now people consider it a truism that non-native plants simply move into an area and push out native species.

But Mr. Tallamy’s presumption was made without consideration of the prior history of his newly acquired parcel. The Tallamys had purchased land that “had been farmed for centuries before being sold and subdivided.” What had actually happened was that alien plants colonized barren, abandoned, nutrient-poor farmland with a disturbed soil profile—something I’ve watched happen in Virginia since I was a college student in the 1970s.

At that time, the Eastern Redcedar (Juniperous virginiana) was the bane of many a cow farmer because these native trees constantly tried to move into their fields of compacted soil bereft of organic matter (other than cow pies) for who knows how long.  This phenomenon was, and still is, something that can be observed, especially along I-81.  Over the years, I’ve gotten off the highway numerous times to document it in photos.

By the 1980s, cow fields along I-81 were beginning to be abandoned. I noticed how they filled eventually—I’m talking years—with either redcedars or non-native Autumn Olive shrubs (Eleagnus umbellata), or a mix of both. Doug Tallamy’s land had likewise taken years to become “at least 35%” non-native vegetation because he mentions removing Oriental Bittersweet (Celastrus orbiculatus)—vines considered invasive—that had 6-inch-caliper trunks. That size isn’t reached overnight.

Therefore by the time he started to remove non-native plants, they’d had time to accomplish some degree of soil rehab, which is why some native trees could grow at that point. He can be forgiven his misperception because, unless you’ve been paying attention for decades, as I have, you won’t have a clue about this process.

The fact is that most yards are rather similar to cow fields, except that their soil profile has been totally rearranged by land clearing and grading. This was, in fact, the situation when I moved into my house almost 30 years ago.

The cleared and re-graded land had exposed gray clay subsoil in most of the yard.  As someone who’d been enthralled by astronomy since the age of seven, I couldn’t help thinking my back yard looked like the surface of the Moon! The rest of the yard consisted of the more-typical Virginia red clay.

Obviously there was no way that I could personally improve such a large amount of soil for the sake of native plants. It would take years of rehabilitation, mostly executed by non-native plants that didn’t mind one bit growing in a disturbed soil profile.

Thanks to alien plants, my moonscape very quickly became a nature-friendly garden that supported an incredible diversity and abundance of wildlife—even more so than had existed here when the land was deeply shaded by forest.

I’d spent time on the property throughout the seasons to document wildlife usage before a small area was cleared where my house was to be built. I discovered that it’s a myth that mature forest is the pinnacle of wildlife abundance.

The reality is that it supports nowhere near the amount of life that a field (or meadow) habitat is capable of supporting—and a field habitat is exactly what most yards can be easily transformed into! Although you may immediately think “ugly” when envisoning a field, you shouldn’t.

When I talk about creating field habitat around your house, I’m referring to the incorporation of the qualities of a field: an open area with a large variety and number of herbaceous plants, surrounded by shrubs and trees to create edge.

I am not implying that your yard must be totally wild and unkempt, although the more natural it is, the better it will provide for life. Rest assured, a nature-friendly garden can be very nice looking.

Even though many species of native plants have naturally moved into my yard over the decades as the soil has improved, I would never completely remove the alien plants I deliberately brought into the yard many years ago. They are so beneficial to wildlife that, in fact, they have sometimes been life-saving.

Several years ago, deer consumed most of the native herbaceous plants in my yard and took most of the leaves off small native shrubs and trees. As a result, the denuded woody plants were unable to produce fruits. To add insult to injury, the following winter was very cold and snowy, which meant fruit-eating birds were in desperate straits.

But luckily for a flock of bluebirds that visited my yard that winter, my Japanese Barberries (Berberis thunbergii)—shrubs that deer do not normally feed upon—held numerous small red berries which the birds consumed over the course of a few days.

Japanese Barberry can spread and is thus considered invasive, yet it can’t be denied that those bluebirds—a species that is not commonly seen in my yard—were aided by it. They were obviously on the move, desperately seeking food which they found on my deer-ravaged property where only some kinds of alien plants had been left alone by the hoofed browsers.

Indeed, the many years of overpopulated deer herds have played a significant role in the enablement of so-called invasive plants. By keeping areas cleared of native plants, deer created opportunities for alien plants to move in. In actuality, the invasive-plant situation cannot be dealt with realistically until deer numbers are truly kept in balance with the environment.

I’ve seen far more wildlife—both in species and in numbers—in my yard over the past three decades than most folks will ever see in a lifetime of visiting wildlife refuges and national parks. As a result, I know that non-native plants are not only beneficial to wildlife, but also to soil rehabilitation that allows native plants to show up when conditions are suitable for their survival.

There are certainly situations in which alien plants shouldn’t be introduced, but most yards don’t fall into that category. In a world overrun by humans, with wildlife struggling to survive on our terms, it’s foolish to suggest that non-native plants should be removed (usually by using herbicides) on private property that is in no condition to support native plants.

It’s a myth that non-native plants do not provide adequate food, shelter, and nesting sites for many kinds of wildlife; in fact, many non-native plants are remarkably nature-friendly.

In part two of this article (which will appear in the August issue), I’ll discuss five woody non-native plants in my yard that have been the most valuable to the critters in my area. I’m sure you’ll be surprised.


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