Winter Kill Alert For Bermudagrass Golf Courses
Jan. 6, 2010
By Bud White, Director, USGA Mid-Continent Region, USGA
and Jim Moore, Director, Construction Education Program, USGA
The arctic front that is rapidly moving across the southern portion of the country is bringing conditions that include well-below freezing temperatures that may persist for multiple days. This represents a real danger to bermudagrass golf courses – particularly bermudagrass greens.
This recent image from a southern course illustrates the contrast between frozen and non-frozen turf. (Jim Moore, USGA)
Bermudagrass is a warm season turfgrass that enters a dormant state after the first hard frost of the year. Although the top of the plant (the leaves) are brown and appear dead, the underground portions of the turf (stolons, rhizomes, and roots) are alive. The turf will return to active growth when warmer temperatures return in the spring. The soil serves as a buffer to protect healthy bermudagrass, but when temperatures drop to well below freezing or are sustained over many days, even the underground plant parts can freeze and die.
The severity of the kill depends on many factors, including the health of the turf going into the winter, the amount of traffic the area receives, shade (which results in lower temperatures), and the height that the turf is mowed. As a general rule, the lower the height of cut, the greater the likelihood of damage. This is why greens are more susceptible than other areas of the golf course.
Superintendents all across the South are taking steps to protect their greens as best as possible during this critical period. This includes applying water to ensure good soil moisture, restricting traffic, and, when possible, using covers or blankets on the greens. Even a 3 mil plastic cover can provide a protective barrier to help moderate soil temperatures on greens. Covers can be very effective, but they are expensive and labor intensive to put out, so many golf courses cannot afford them.
And one more thing, golfers should be aware that the turf is still susceptible to damage after the surface thaws. Most golfers are accustomed frost delays - as soon as the frost burns off, play begins. Soil freezing is another matter, and often after a sustained period of freezing temperatures the course must be closed for additional time to allow the frozen soil to dissipate. If the turf thaws on the top but remains frozen a half inch below the soil surface, traffic will shear the turf from the roots or rhizomes, and the result is a lot of dead grass.
Your golf course superintendent will be out there doing everything possible to minimize the potential trouble, but, in spite of these efforts, damage can still occur and some replanting may be necessary next spring. Keep your fingers crossed that the meteorologist’s predictions prove less dire than what is anticipated.