Non-native Plants Can Be Remarkably Nature-friendly, Part One

 

© Marlene A. Condon
July, 2015

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, 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.

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

Non-native Plants Can Be Remarkably Nature-friendly, Part Two

© Marlene A. Condon
August, 2015

Not all non-native plants are created equal, nor are all yards suitable for their introduction. If you live near a natural area that is composed primarily of native plants, or if you live near wetlands, then you certainly should try to avoid growing alien plants that might spread into these relatively un-degraded areas.

However, if you want to start helping wildlife even though your yard consists mostly of subsoil, which is not very conducive to the growth of native plants, there are numerous alien plants that are already part-and-parcel of our environment that are wonderfully nature-friendly. I’ll start with three non-native woody plants I originally chose for their red foliage—my favorite color.

When I planted Chinese Photinia (Photinia serrulata), I had no idea how valuable this multi-stemmed shrub would be to wildlife and my wildlife viewing. In winter, Dark-eyed Juncos and White-throated Sparrows sleep among the branches, being replaced by Northern Cardinals and Eastern Phoebes in spring. I’ve even had an Eastern Screech Owl perch in there while waiting for darkness to descend on late-winter and very early-spring days.

What I’ve found most interesting, however, is the heavy use of these plants by Yellow-bellied Sapsuckers. Birds of the north that migrate to Virginia for the winter, these woodpeckers use their beaks to drill small holes (“wells”) into the bark of trees from which sap oozes. This sweet liquid provides them with carbohydrates, a source of quick energy.

Sapsuckers have visited my photinias regularly throughout the decades and it’s obvious. An inspection of the trunks reveals rows and rows of old and new sap wells, an undeniable sign of the affinity these birds possess for photinia sap. But they aren’t the only ones that want a sweet drink! Tufted Titmice, Carolina Chickadees, Downy Woodpeckers, flying insects (on warmish winter days), and even Gray Squirrels visit the wells.

And as if this wildlife usage wasn’t enough, the small white spring flowers attract so many bees that you can hear the loud buzzing well before you are within sight of the plants, and the resulting red fruits feed birds and mammals come fall.

My plants are almost 30 years old but have never produced a seedling, so Chinese Photinia is not likely to spread of its own accord. I should warn you that the flowers don’t smell very good, but because the blooming time is rather short, it’s not something you have to put up with for a long time.

Lastly, to take advantage of all of the benefits these plants offer to wildlife, they should be allowed to grow into their natural shape and height (up to 30 feet tall), rather than grown as a constantly sheared hedge, as is so often done. Photinia hedges are almost invariably doomed to leaf spot (caused by a fungus) because the pruning causes a thick growth of leaves that can’t get good air circulation to dry them.

It should also be noted that pruning is injurious and really shouldn’t be done unless it’s absolutely necessary. Woody plants can handle a bit of pruning because they’ve evolved with animals that feed upon them, which of course, prunes them. But too much feeding by animals or pruning by people can kill plants.

I love the red leaves of Japanese Maple (Acer palmatum), but I also love its value to wildlife, which came as quite a surprise and delight!

When the trees’ buds start to swell, they are ready to be eaten by Gray Squirrels and White-throated Sparrows that visit often. The buds they miss develop into blooms that bring the insects swarming: flies, wasps, a multitude of tiny bees, and butterflies, such as the Spring Azure and Tiger Swallowtail. The resulting seeds are eaten by Gray Squirrels.

Japanese Maples are very slow-growing trees, so you’ll be resigned to enjoying only their beauty until their wildlife potential develops.

I first became familiar with Burning Bush (Euonymus alatus) when I was a college student at Virginia Tech. A yard I walked by on my way to town had a huge specimen that was spectacular in the fall when its leaves turned a bright red. I knew I had to have one of these plants some day when I was permanently settled somewhere!

Although bashed as an invasive plant, Burning Bush is useful to many kinds of animals. The little yellow spring blooms attract a variety of tiny insects, especially bees. Small winged fruits develop that feed Northern Cardinals and White-throated Sparrows as well as Gray Squirrels. And in late winter, Dark-eyed Juncos and White-throated Sparrows visit daily to feed on the enlarging buds.

I’ve observed White-tailed Deer eating the leaves of Burning Bush. However, they only began to feed on this plant in the past few years as deer numbers were exploding in Virginia, suggesting it’s not a preferred food plant for them.

Burning Bush is originally from Asia and can indeed spread. But my own yard is so full of plants that most so-called invasive plants struggle to stay put, never mind increase in number (the reason I know experientially that these plants need a cleared area before they can start growing somewhere). If Burning Bush could be troublesome in your area, you probably shouldn’t grow one in your yard.

The Summer 2012 issue of the Butterfly Gardener was devoted to “The Great Butterfly Bush Debate” in which two butterfly gardeners took opposing stands on whether or not people should grow Buddleia davidii. This shrub, which has been widely planted as a nectar source for butterflies, is yet another plant from Asia that has spread beyond the gardener’s gate by way of seed production.

I have a Butterfly Bush that certainly does bring in butterflies. It does make seeds, but I’ve yet to find a seedling in my yard. Where I have seen this plant as an escapee from the home garden is along miles and miles of train tracks, which isn’t surprising. Just like other plants that are referred to as invasive, Butterfly Bush can tolerate the wretched growing conditions provided courtesy of the railroad companies.

Luckily, you don’t need to grow Butterfly Bush. If you want a shrub attractive to butterflies (and bees), I highly recommend Glossy Abelia (Abelia x grandiflora) as a substitute. Developed from plants native to Asia and Mexico, this hybrid does not make seeds and thus does not move out of the area. It blooms from spring until frost, making it the perfect substitute for Butterfly Bush if your yard has poor soil.

Shrubs and small trees, unlike flower beds, do not take much effort to maintain. If you want to help wildlife without a lot of fuss and bother, by all means grow woody plants such as the ones I’ve mentioned here (with the exception, perhaps, of Burning Bush).

But to bring in the highest number of wildlife species, you require flower beds that contain a diverse array of plants in abundance, whether they are native or naturalized (which is really what “invasive” means). The easiest way to find out what will grow best in your soil is to clear a bed for plants and see what comes up. Those are the plants best suited to your growing situation and that will provide for wildlife.

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