In the 1990s, Dr. James Read of Texas A&M University, successfully crossed Kentucky bluegrass (Poa pratensis) and Texas bluegrass (Poa arachnifera, a bluegrass species native to the Panhandle of Texas). He named the first commercially available variety ‘Reveille.’ There are several potential advantages to using these Kentucky x Texas bluegrass hybrids for lawn and sports turf applications in Colorado. The following observations and comments are based on limited research at CSU, as well as field observations and testimonials from sod producers and those who have planted these hybrids in the Western United States. A list of commercially available hybrid bluegrass cultivars is found in Table 1.
- Excellent heat tolerance. This grass seems to grow better the warmer it gets in the summer. The growth and vigor of most Kentucky bluegrass varieties will decline under high heat (upper 80s to 100s), which can reduce its traffic and wear tolerance during the hottest times of the growing season. The hybrid bluegrasses maintain more active summer growth, which translates into better traffic tolerance and ability to recover from traffic injury.
- Deep and extensive root production. These hybrids produce an extensive root system, which can enhance heat and drought resistance. A dense root system will also improve traffic tolerance, ability to recover from wear, and will improve footing (traction) in a sports turf application.
- Extensive and aggressive rhizome formation. These grasses form large, extensive, and aggressive rhizomes (underground stems). Different from roots, rhizomes contain growing points that produce new grass plants. Grasses that produce rhizomes are better able to tolerate traffic and will recover more quickly from traffic-induced wear – often without the need to reseed the worn areas. An aggressive rhizome system also means better traction in a sports turf situation.
- Low mowing height tolerance. Its excellent heat tolerance and aggressive root and rhizome formation characteristics allow this grass, when necessary, to be mowed at lower heights than many Kentucky bluegrasses – especially during the heat of summer. This can be important for “showcase” sports turf applications.
- Potential to require less irrigation. Variability exists among the hybrid bluegrasses regarding irrigation requirement and drought resistance. Research has shown some of them possess very good drought resistance (compared to other bluegrasses, and even to tall fescue), while other varieties have moderate or poor drought resistance. The ability to sustain growth and vigor with less irrigation results from deeper roots and its excellent heat
Table 1. Commercially Available Hybrid Bluegrass Cultivars
| Cultivar |
|---|
| Armadillo |
| Bandera |
| Dura Blue |
| Fahrenheit 90 |
| Fire and Ice |
| Longhorn |
| Solar Green |
| Thermal Blue |
| Thermal Blue Blaze |
This publication, reference GardenNotes #563, is developed as part of the Colorado State University Extension Master Gardener Program.