Turfgrass species characteristics for roadsides

Tue, 07/09/2019 - 12:00

By Dominic Christensen

Turfgrass species are often planted to revegetate roadsides after construction, especially in cities and urban areas. Their short-stature growth habit gives drivers better visibility than shrubs or trees. They can also function as a buffer strip to reduce pollutant loading, recharge groundwater, and reduce erosion, among other benefits (Beard & Green, 1994; Friell, Watkins, & Horgan, 2015). Mixtures of turfgrass species are often used because one species cannot tolerate every stress and certain species may be more suited in particular environments (Friell et al., 2015). Furthermore, planting mixtures of these species enhances the biodiversity and resilience of these systems. This article highlights the rationale for use of individual species along roadsides, their advantages, and disadvantages in Minnesota or in regions with a similar climate. These are the species currently being tested in the MnDOT regional mixture trial. Stay tuned for a future blog post highlighting general characteristics of other species along roadsides such as bluegrama, prairie junegrass, Canada bluegrass, and more!

Kentucky bluegrass

Rationale: To give roadsides a “front-lawn” look that is dense and aesthetically pleasing if well-maintained. Unfortunately, Kentucky bluegrass is the most popular and cheapest sod available and that translates to its overuse along roadsides.

Advantages	Disadvantages
Dense rhizomatous growth habit Dormancy mechanisms allows it to survive long periods of drought Winter hardy	Poor salt tolerance—often its greatest limitation (Alshammary, Qian, & Wallner, 2004) Slow to establish from seed Requires more mowing and is not suited to low-maintenance conditions

turfgrass seedlings emerging through erosion blanket — Figure 1. Kentucky bluegrass slow establishment in Fergus Falls, MN.

Fine fescue

Rationale: For use on all types of roadsides as a low-maintenance grass that has medium tolerance to a variety of stresses. Arguably the most adapted group of short-stature species for use along roadsides. The term fine fescue < http://lowinputturf.umn.edu/ > refers to a group of five turfgrasses (strong creeping red fescue, slender creeping red fescue, hard fescue, sheep fescue, and Chewings fescue).

Advantages	Disadvantages
Requires less mowing, nutrient inputs, and general maintenance More tolerant of poor soil conditions and some fescues have excellent salt tolerance Usually one of the top performers in roadside research projects (Friell et al., 2015)	Some species require more time and water to establish Less tolerant to high foot-traffic areas Susceptible to death when mowing occurs during periods of drought and excessive heat

Young fine fescue plants in plots alongside a curb — Figure 2. Fine fescue plots in East Grand Forks, MN.

Perennial ryegrass

Rationale: Planted to reduce soil erosion quickly in highly erosive environments. Adapted as a cover crop to allow slower establishing species time to establish.

Advantages	Disadvantages
Quick germination and establishment Tolerant to high foot-traffic areas	Species is highly unlikely to persist after two to three years due to poor winter hardiness Poor salt tolerance Greatly interferes with mixture success when present in quantities greater than 10% (Henensal, Arnal, & Puig, 1980)

three perennial ryegrass plants — Figure 3. Perennial ryegrass establishes quickly.

Alkaligrass

Rationale: Alkaligrass is tolerant to alkaline soils that experience significant salt from winter deicing practices. Its slower establishment and poor competitive ability in a mixture limits its persistence.

Advantages	Disadvantages
Highly salt tolerant Winter hardy Well-adapted in monoculture stands nearest to an uncurbed roadside (Friell, Watkins, & Horgan, 2012)	Poor competitive ability in a mixture (Friell et al., 2015) Limited use as a managed turf system Requires more water and fertility than other low-input species

Advantages

Disadvantages

Highly salt tolerant

Winter hardy
Well-adapted in monoculture stands nearest to an uncurbed roadside (Friell, Watkins, & Horgan, 2012)

Poor competitive ability in a mixture (Friell et al., 2015)
Limited use as a managed turf system
Requires more water and fertility than other low-input species

plot of alkaligrass along roadside — Figure 4. Alkaligrass seedheads in Roseville, MN.

alkaligrass along a curb — Figure 5. Alkaligrass along a highway in New Jersey. Photo courtesy of Brad Park, Rutgers University.

Tall fescue

Rationale: Tall fescue is commonly planted along roadsides in the transition zone of the United States (i.e. in the central United States). It was originally a forage grass and turf-type varieties offer some desirable characteristics for its use along roadsides.

Advantages	Disadvantages
Deep roots allow it to withstand drought Quick germination and establishment Moderate shade tolerance and foot-traffic tolerance	Poor tolerance of long-term ice cover Slow spring green-up in cold climates

Sparsely growing turfgrass on left and turfgrass with more growth on right — Figure 6. On the left, tall fescue exhibiting less coverage closer to the curb. On the right, the same plot further from curb shows greater coverage.

Buffalograss

Rationale: Buffalograss is a warm-season native grass commonly found in the Great Plains. It grows together naturally with blue grama in the environment. It is highly adapted to low-maintenance environments. This species is only adapted for drier and warmer regions of Minnesota, such as southwestern and western Minnesota.

Advantages	Disadvantages
Excellent heat and drought tolerance Stoloniferous growth habit fills in gaps	Slow establishment Expensive seed Poor shade tolerance

Buffalograss growing alongside a road — Figure 7. Buffalograss (along with some flowering white clover) along a roadside.

References

Alshammary, S. F., Qian, Y. L., & Wallner, S. J. (2004). Growth response of four turfgrass species to salinity. Agricultural Water Management, 66(2), 97–111. https://doi.org/10.1016/j.agwat.2003.11.002

Beard, J. B., & Green, R. L. (1994). The Role of Turfgrasses in Environmental Protection and Their Benefits to Humans. Journal of Environmental Quality, 23(3), 452–460. https://doi.org/10.2134/jeq1994.00472425002300030007x

Friell, J., Watkins, E., & Horgan, B. (2012). Salt tolerance of 75 cool-season turfgrasses for roadsides. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science, 62(sup1), 44–52. https://doi.org/10.1080/09064710.2012.678381

Friell, J., Watkins, E., & Horgan, B. (2015). Cool-season turfgrass species mixtures for roadsides in Minnesota. Ecological Engineering, 84, 579–587. https://doi.org/10.1016/j.ecoleng.2015.09.057

Henensal, P., Arnal, G., & Puig, G. (1980). Research into the Establishment of Roadside Embankments. Proceedings of the Third International Turfgrass Research Conference, acsesspublicati(proceedingsofth3), 391–400. https://doi.org/10.2135/1974.proc3rdintlturfgrass.c45