This winter will be one to remember for many golfers in the south-central part of the country. The winter storm that swept across Texas, Oklahoma, Louisiana, Arkansas and Mississippi brought cold temperatures that are typically not expected. Unfortunately, extremely low temperatures can be lethal to bermudagrass, which makes up the playing surfaces on many golf courses in the southern part of the U.S. We do not know the extent of the damage yet and it is impossible to predict with total accuracy because the mechanisms of winterkill are not completely understood. However, it won’t be long before golf courses may begin to see the impacts of the cold weather on bermudagrass greens, tees, fairways and roughs.
Creeping bentgrass and other cool-season grasses are more tolerant of freezing temperatures, so they should not have been affected by the winter storm and generally can be expected do fine during southern winters. The downside to these grasses in southern parts of the country is that they are not well-adapted to the sustained hot and humid conditions that persist through the summer.
While there is no guaranteed way to prevent winter injury, there are a few precautions that superintendents can take in advance of cold temperatures to help protect bermudagrass throughout the golf course:
- Superintendents prune or remove trees that create shade to increase sunlight and raise the winter temperature on playing surfaces.
- Although counterintuitive, some superintendents apply overnight irrigation if freezing temperatures are forecasted for only a few hours. This moisture can actually increase temperatures around the plant to provide short-term protection from freezing weather.
- A variety of tools, like portable moisture meters, are used to ensure the grass has adequate moisture so it is less susceptible to cold-temperature injury.
- Drainage is installed in low areas to prevent water, snow and ice from accumulating and damaging the grass.
There are also some specific precautions that are taken to protect ultradwarf bermudagrass putting greens:
- Some superintendents spread sawdust, mulch, hay or pine straw over bermudagrass putting greens before cold weather to insulate them from freezing temperatures.
- Covers provide the best level of protection for bermudagrass greens during freezing temperatures. These specialized tarps are often deployed to cover putting greens and insulate them from freezing conditions, especially when temperatures are forecast to fall below 20 degrees Fahrenheit.
- When temperatures are expected to persist below 20 degrees Fahrenheit for several consecutive days – or temperatures drop into the single digits – a combination of tactics are often used to protect bermudagrass greens. By placing pine straw or fixed materials like drainage pipe or pool noodles on a putting surface and then covering it, superintendents create an air gap between the cover and the turfgrass surface. This air gap creates an extra layer of insulation that can make a big difference during extremely cold weather.
Covers can be particularly helpful for preventing winter injury on bermudagrass greens. Historically, courses that have experienced damage on greens in winter did not have covers or only had covers for some of their greens. Having covers is a lot like having insurance – you hope you don’t need to use them, but after one devastating winter you will wish you would have! While covers are an effective way to protect bermudagrass putting greens during freezing temperatures, they do not offer an absolute guarantee that winter injury will not happen and it only takes one very cold night for damage to occur.
Looking forward, acquiring putting green covers will offer some peace of mind and insurance for courses with bermudagrass greens. For other areas of the course that are too large or difficult to cover, such as fairways and tees, now may be the time for courses to plant grass varieties that are better able to withstand cold temperatures. The USGA has invested significant amounts of money in turfgrass research to develop warm-season grasses that can handle colder winter weather.
Depending on location, good growing conditions for bermudagrass might not return until late May or early June. Until then, it will be a waiting game to see if warm-season grasses survived the winter. Be patient as superintendents are eagerly preparing for the return of favorable weather. After a challenging winter, you can rest assured that the knowledge and skill of the golf course maintenance staff will have the course in great condition as soon as possible so you can focus on making plenty of pars and birdies.