Kentucky Bluegrass in a Semi-Arid Climate
Most Bozeman lawns predominately feature a single grass species commonly referred to as Kentucky bluegrass or Poa pratensis. This cool season plant is known for its dense, lush, and high-traffic durability features that we often desire on our local sports fields, community parks, and residential landscapes. Native to most of Europe and Northern Asia, Kentucky bluegrass thrives in cool, wet conditions and therefore struggles to adapt to Bozeman’s semi-arid and drought-prone climate. As a result, frequent and substantial irrigation events are required to maintain the lush appearance of our local Kentucky bluegrass lawns.
In 2015, MSU and the City of Bozeman teamed up in search of a climate-adapted turfgrass alternative that could still produce the same lush and durable lawns we love, while requiring far less supplemental irrigation. Given that over 50% of Bozeman’s water heads straight onto our landscapes, developing drought tolerant turfgrass alternatives could help extend our local water supply substantially!
Putting Turfgrass to the Test
Featured along the North and South 27th Ave medians, you might have observed our turf grass alternative trials in action while driving around town.
In 2015, a variety of climate-adapted Fescue species and Kentucky Bluegrass were seeded along these medians and analyzed based on weed susceptibility, grass density, soil moisture, soil chemistry, and supplemental watering requirements over a study period of two years.
Treatments, species and cultivars utilized in this study include:
- Bare ground
- Shredded Cedar bark mulch
- Festuca ovina glauca 'Blue Heron' – blue sheep fescue
- Festuca trachyphylla 'Blueray' – hard fescue
- Festuca trachyphylla 'Sword' – hard fescue
- Festuca rubra 'Boreal' – red fescue
- Festuca rubra 'Marvel' – red fescue
- Festuca ovina 'Covar' – sheep fescue
- Poa pratensis ‘SPF-30’ - Kentucky bluegrass
- A seed mix including Blue Sword, Heron, and Boreal Fescue.
Fescue to the Rescue!
Data shows that while individual Fescue species require less supplemental watering (once established) compared to Kentucky Bluegrass, no single species or cultivar performed better than another. However, when blending individual species together, we found that each included species’ and cultivar’s best qualities coalesced to form a mix that more successfully suppressed weed growth and rapidly increased ground coverage, compared to any one individual. That is to say, when installing turfgrass alternatives on our local landscapes, it is recommended that a Fescue seed blend be utilized to maximize performance and water efficiency.
Alternative Grasses in Action
Did you know that our drought tolerant seed mix has already been installed around town? In 2021, the medians along N 27th Avenue between Oak St. and Baxter Lane were installed with a fescue blend seed mix based upon the results of this study. The same seed mix comprises 83% of the total grass area at Bozeman’s new Public Safety Center. Not only is this climate-adapted grass mix saving water for our community, but it’s also reducing maintenance costs by significantly reducing the need for mowing.
The City of Bozeman aims to exemplify our commitment to water conservation by implementing water-smart landscapes all around town. By utilizing the results from our North and South 27th Ave median experiment in future City projects, installing climate-adapted lawns is just one way we’re inspiring the community to move towards a water-smart future!