Inhibiting Invasive Plants in Roadsides through Selection of Eurasian Grass or Native Seed Mixtures.

Roadsides are artificial environments subject to invasive plants which may be regulated by certain states.  Our goal was to assess the amount and types of invasive plant species and identify predictors of planted and invasive plants along Wisconsin roadsides.  Vegetative surveys were conducted along 35 roadsides in 13 counties during 2011-2012 along three distinct zones parallel to roads.  Soils were sampled at each site and assessed for pH, organic matter, soluble salts, P, K, and texture.  Slope aspect and inclination, surrounding land use, climatic data, and seeding mixture used for establishment were used along with soil characteristics in ANOVA and regression tree analysis to identify characteristics related to the presence or absence of invasive plant species.  Type of vegetative cover differed based on seed mixture, stand age, and amount of vehicular traffic.  Native plants failed to successfully establish, and such sites were populated by both non-invasive and invasive plants.  Grasses comprised most of the invasive plants.  Highway agencies and managers could use these data to reduce the potential of invasive species by enhancing establishment of desired Eurasian grasses with inputs such as timely mowing and establishment methods.