Guide to Increasing and Sustaining Native Flora in Roadside Vegetation

Summary

The University of Minnesota Department of Horticultural Science is well positioned to execute this project. As part of a land-grant, R1 research university, our team can leverage multiple strengths, along with our long record of roadside vegetation research and outreach to provide stakeholders with clear, data-driven recommendations.

Our team has years of experience with roadside research and is aware of the important ecosystem services that roadside vegetation provides, including erosion control, dust control, protection of water quality, cooling effects in urban heat islands, and even the social value of human connection to nature that results from additional greenery in urban and suburban landscapes. These services, along with maintaining public safety, are the minimum functions that the public requires of roadsides.

However, the ecosystem services provided by roadside plantings can be greatly expanded with the use of native plant species and the many additional benefits they provide. Native forbs can provide nectar and pollen to benefit native pollinators. Insects such as native butterflies will need native host plants on which their larvae can feed. Native grasses have deeper roots to protect the soil and gather moisture to survive without the need for supplemental irrigation. Both native forbs and grasses can have seed for native birds. People can feel joy at the sight of native flowers in bloom or the colorful fall foliage of native grasses. The list goes on. There are millions of acres of roadsides in our country, and these landscapes have the potential to greatly multiply these ecosystem services.

It may seem native plant species should be adapted to roadsides when they are within their historical native ranges. However, we can?t count on native species to be necessarily fully adapted to roadsides, as roadside environments are often significantly different from natural ecosystems. Roadsides can be disturbed or artificially created/altered with non-native soils that become compacted and have weed seed banks that are filled with noxious invasive weeds. The conditions that occur on roadsides are more harsh than natural ecosystems due to vehicle pollutants, heat stress, drought stress, poor drainage, deicing salts in temperate and cold climates, traffic (from stalled vehicles, snowmobiles, ATVs, and maintenance equipment) and defoliation stress from the mowing required to improve sightlines and safety. Thus, roadside revegetation systems need to factor in these stresses along with specific site characteristics.

Ours is an academic, multidisciplinary team with proven results in all the fields (applied economics, behavioral economics, applied plant science, socio-ecology) this project requires. With our many years of experience conducting research that has supported the Minnesota Department of Transportation and other public agencies in efforts to manage roadside vegetation, our researchers are in a prime position to address the familiar struggles of other state departments of transportation in establishing and managing roadside native plants.