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Our project addresses two critical needs: to update existing MnDOT turfgrass recommendation lists and to develop a new process to keep lists continually updated in a fair manner with data-driven recommendations. We evaluated the current list of MnDOT-approved turfgrass varieties and found underperforming varieties that should be removed. We then found new, improved varieties that should be considered for inclusion on the MnDOT lists. To facilitate a process to keep lists updated for the future, we first conducted a survey of seed distributors. Using their input, we developed a new process that MnDOT can use to approve turfgrass varieties for inclusion as official seed mixtures. Ultimately, this will lead to a more nimble, consistent, and clear process so that existing and new seed vendors can have complete confidence in data-driven decision making by MnDOT.

Current MnDOT specifications for roadside turfgrasses suggest statewide planting of mixtures that are grouped into five broad categories such as low maintenance turf and high maintenance turf. The objective of this research was to identify turfgrasses that possess traits necessary to survive in the harsh roadside environments found throughout Minnesota. We investigated the impacts of possibly the three most limiting environmental conditions (heat; salt and ice cover) on multiple cultivars from up to fifteen individual turfgrass species. Salt stress screening revealed several species with good levels of adaptation including alkaligrass and tall fescue. In the heat stress trial; we found cultivars and selections of Canada bluegrass; tall fescue; Kentucky bluegrass; strong creeping red fescue and slender creeping red fescue were among the top performers. Finally; in our ice cover screening; tall fescue and Chewings fescue did well; however; these results did not correlate well with our typical field observations. For each of these stresses; we identified top-performing cultivars that will be evaluated in field studies with the goal of identifying optimized mixtures for stakeholders in Minnesota.