Environmental Review Toolkit
Water, Wetlands, and Wildlife


Roadside Use of Native Plants

Introducing A Roadside Land Ethic — It's Common Sense

J. Baird Callicot, University of Northern Texas, and Gary K. Lore

"A thing is right if it tends to preserve the beauty, integrity, and stability of the biotic community; it is wrong when it tends otherwise. "
Aldo Leopold "The Land Ethic" A Sand County Almanac.

When Aldo Leopold formulated his now famous land ethic half a century ago, few people realized the utility, beauty, and intrinsic value of roadsides. Economics controlled the use and management of roadsides with little attention to the roadside environment. The time has come for us to recognize that the land ethic applies to our roadsides no less than to our wilderness areas.

Sitting on the mower or on the Department of Transportation budget committee, operating as a design engineer, a snow plow driver or landscape architect, we make decisions that affect our roadsides virtually every day. We usually base these decisions on cost, ease of operation, and safety to the highway user — all highly practical and common sense concerns. Yet, we rarely carefully consider how the consequences of our decisions impact the roadside environment.

Economics can not — and ought not — be the sole determinate of how we treat our roadsides. We must carefully measure not only the present value of any management practice, but also its future economic and environmental costs. All too often we tend to over-value the present and under-value the future, or ignore it altogether. We should seek not economic expediency, but rather the right thing to do by taking a common sense look at the long-term economic and environmental consequences. We should recognize the function, beauty, and intrinsic value of our roadsides and thus our responsibility to properly maintain and care for them. Only by carefully planning our roadside activities with an understanding of roadside ecology can we make the right decisions.

Roadsides provide a buffer between the roadway and the commercial, industrial, agricultural, and other economic activities on the adjoining private lands, protecting both the private land owner and the highway user from one another. Maintaining that protection is our responsibility. Understanding the ecology of the roadside plant community leads to providing that protection. For example, we know that non-native invasive plant species — weeds — follow our roadways, taking advantage of our roadside maintenance practices. Very often, such weeds not only clearly threaten the adjacent land owners economic activities, but also fail to protect the highway user's interests.

Preventing the spread of non-native invasive plant species to our neighbor's property is our responsibility. Year after year roadside crews mow weeds — usually with flail mowers — after their seeds have matured.

While minimally complying with the local weed district's directives, the mowing assures the spread of the weeds. Similarly, many jurisdictions, more out of habit than proven need, mow native grasses and forbs before their seeds mature. The flail mowers expose the soil for the weed seed, giving them a competitive advantage, cultivating even more weeds to mow or spray in the future. That makes very little sense. We must avoid and prevent activities that give weeds an opportunity to spread.

Our roadsides contain important remnants of our nation's biological heritage. Though by definition roadsides are not wilderness or wildlife areas, in many parts of our country, they remain the only safe harbor for many native plants and songbirds. It makes little sense to unwittingly destroy their habitat.

Roadsides also provide increasingly important places of beauty, respite and interest to the highway user, as Aldo Leopold pointed out in A Sand County Almanac, "every highway is bordered by an idle strip as long as it is; keep cow, plow, and mower out of these idle spots and the full native flora ... could be part of the normal environment of every citizen".

Natural beauty is not limited to mountains, coastal vistas, pine forests, geological sites, or lakes and rivers. Many highway users discern more aesthetic satisfaction and simple pleasure in viewing an autumnal roadside of prairie flowers and grasses than we have yet been able to measure, or value. Interesting roadsides also help keep highway users alert and attentive, providing for greater safety. Protecting that beauty and interest makes better sense than needlessly destroying it.

We should also carefully consider our efforts to change or "improve the roadsides". Roadsides naturally change, from season to season and from year to year. Yet, arbitrary and artificial changes to roadsides are usually more detrimental, violent, and disruptive than natural changes. Instead of improving roadsides, we disturb and destroy their intrinsic natural beauty.

While we can mimic nature when landscaping construction areas, we have yet to master the inner workings of nature. Nature is not only much too complex for us to reproduce, it is unique and irreplaceable. Unlike growing manicured turf grass, replicating natural areas is more costly than simply protecting them.

This is not to say that "nature knows best," but rather that it is extremely arrogant to say that highway engineers, managers or mower operators know best. For example, chemical mowing — once touted as being far less disruptive to the roadsides and more economical than the mowers it replaced — results in the virtually unrestrained spread of some noxious and problem weeds. Basing decisions on poor or incomplete science and ignoring clear evidence insults our common sense.

However, the most profound reasons to protect the beauty, stability and integrity of the roadside plant community are, quite simply, because we can and because it makes sense. In some cases, roadside weeds may do as good a job of preventing soil erosion or other tasks as natives, but we should prefer native plants because they are native. It's the right thing to do, irrespective of the practical or prudent thing to do. We should preserve, protect, and encourage the planting of native plants as a matter of biotic right — and because we love them for what they are in themselves.

Yet, as Leopold also reminded us, "A land ethic of course cannot prevent the alteration, management and use of these 'resources', but it does affirm their right to continued existence, and, at least in spots, their continued existence in a natural state." This means that we must realize that turning our roadsides into highly eroded, barren or weed-infested waste lands, or dump sites for leftover construction materials not only makes very little sense, but also is simply wrong.

Since Leopold, our understanding of roadside management has developed immeasurably, both as a science and as an art. Recognizing our roadsides as valuable treasures and incorporating Leopold's land ethic in our roadside management decisions goes a long way towards following a roadside land ethic that makes sense. Protecting the utility, beauty, and intrinsic value of our roadside biota remains our responsibility. It's the only management decision that makes sense.


Questions and feedback should be directed to Deirdre Remley (deirdre.remley@dot.gov, 202-366-0524).

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