Cloverleaf interchange

By Kaitlin Stack Whitney

White clover along a roadside

Over the past century, a vast network of highways has been built and expanded across North America. In the United States alone, there are 4 million miles of roads and most of the US is within 1km of a road. Roads are everywhere. Roads are designed for efficient, fast, and safe car and truck travel, to carry people and goods. In a lot of places, commuting, communities, and the landscape are now shaped by – even organized around – roads. But road development has not been as positive for wildlife. Roads have long been considered barriers to animal movement and a direct mortality threat to wildlife through collisions.

So what about for plants? Well, the establishment of highway systems inadvertently created an entirely new place: the roadside right of way.

Highway roadsides emerged as physically distinct ecosystems to manage – not simply the line between road and other. And some plants, including ones sometimes labeled “bad” (e.g. introduced species or endemic but “noxious”) thrive in this unique environment.

Trifolium repens, white clover, is one of those. White clover lives on this edge, in the verge. It’s a creeping, herbaceous legume, perennial in much of its global range and thriving in disturbed roadsides. Originally found in Europe, now it’s everywhere – and often planted on purpose in roadside seeding mixes, that’s how well suited it is.

Historically, white clover was used to purify and cleanse the blood. Perhaps now white clover will purify and cleanse our transportation arteries.

According to global monitoring data, there has been a steep decline in invertebrate populations over the past 40 years. White clover provides food and habitat for many livestock and wild animals in grassland areas, but in roadside edges it does something else. White clover there mostly serves invertebrates, like insects. Its leaves, stems, flowers, and seed pods are edible. White clover requires insect pollination as the flowers are self-sterile, and the flowers are attractive to many bees.

Sit and watch it sometime, you may be amazed what stops by. And that’s why I love white clover. It’s life on the edge, life finding a way, poking through concrete or pavement or the lone forb in a sea of grass. White clover is an integral part of imagining and ensuring roads as connector instead of barrier.

Dr. Kaitlin Stack Whitney is an insect ecologist and animal studies scholar, which means she’s also developed an appreciation for plants. She is an Assistant Professor at the Rochester Institute of Technology in the Science, Technology & Society Department. Visit the SWEET Col(LAB)orative on the web at https://pht180.rit.edu/sweetlab/people/, and follow Kaitlin on twitter at @kstackwhitney