Fall 2019 roadside turfgrass mixtures establishment update

By Dominic Christensen

Map of the state of Minnesota marked with the locations of 14 research sites
Figure 1. Research sites.

For part of my master’s research, I am evaluating 40 roadside turfgrass mixtures throughout Minnesota. This fall we established 7 more sites for a total of 14 sites. At each site we are assessing the performance of different turfgrass species and mixtures along roadsides throughout Minnesota (Figure 1). We choose to establish sites in the late summer because soil temperatures are still relatively warm, there is adequate soil moisture (although we installed a temporary drip irrigation system), and weed pressure is low since many summer annuals common on roadsides in Minnesota have concluded their life cycle. Establishing roadsides in the late summer/early fall has also been supported by some of our other roadside work.

Table 1. Seeding dates for each location

Location Seeding date
Bemidji 08/26/19
International Falls 08/28/19
Duluth 09/06/19
Saint Cloud 09/18/19
Willmar 09/11/19
Edina 08/30/19
Worthington 09/14/19

In general, we had much better establishment this fall at our newest seven sites because we established them a bit earlier than the fall 2018 sites and temperatures remained warmer. The dates we established each site is shown in Table 1. A photo of fall establishment from each new location is shown below (Fig. 2-8). The Duluth site is lagging behind our other 6 sites because we established it late and it got cold earlier than we were expecting. The site has been reestablished by several contracting companies and been found to be especially problematic. We noted poor soil conditions and numerous sporadic boulders just beneath the soil surface during our install at Duluth.

roadside research plots with turfgrass seedlings in Bemidji, MN
Figure 2. Bemidji, MN, October 16, 2019
roadside research plots with turfgrass seedlings in International Falls, MN
Figure 3. International Falls, MN, October 17, 2019
roadside research plots with turfgrass seedlings in Duluth, MN
Figure 4. Duluth, MN, October 18, 2019
roadside research plots with turfgrass seedlings in St. Cloud, MN
Figure 5. Saint Cloud MN, October 23, 2019
roadside research plots with turfgrass seedlings in Willmar, MN
Figure 6. Willmar, MN, October 22, 2019
roadside research plots with turfgrass seedlings in Edina, MN
Figure 7. Edina, MN, October 15, 2019
roadside research plots with turfgrass seedlings in Worthington, MN
Figure 8. Worthington, MN, October 25, 2019

Evaluating establishment and coverage over time at challenging sites like in Duluth can help us evaluate which turfgrass species are surviving, understand the importance of species diversity, and develop optimized multi-species mixtures. Collecting this data will allow us to recommend new Minnesota Department of Transportation (MnDOT) turfgrass seed mixtures and this will benefit contractors and cities.

This research is supported by a grant, "Regional Optimization of Roadside Turfgrass Seed Mixtures Phase 2: Regional Field Trials and Economic Analysis", from the Minnesota Department of Transportation and the Minnesota Local Road Research Board.