Key Takeaways

• Two studies were conducted in the summer of 2021 at Lehigh Country Club in Allentown, Pennsylvania, to evaluate the differences in divot recovery between a hybrid bermudagrass and creeping bentgrass practice tee.
• In both studies, divots on the hybrid bermudagrass tee were more than 50% recovered 14 days after they were created. Conversely, divots on the bentgrass tee took more than 30 days to reach 50% recovery.
• After 40 days, divots on the bentgrass tee remained less than 75% recovered in both studies, while divots on the bermudagrass tee were more than 95% recovered.
• This research confirms that hybrid bermudagrass tees can provide significantly faster divot recovery than bentgrass during summer months, even in areas north of the transition zone.
• Golf courses located in areas that are suitable for growing hybrid bermudagrass should consider using this species if they currently have cool-season practice tees that are unable to keep up with traffic wear during the summer months.
• During the fall, winter and early spring, hybrid bermudagrass may be dormant in northern areas, which means practice must shift to synthetic mats or an alternate tee planted with a cool-season grass.
   

Two separate studies were performed on these surfaces, with initial divots created on July 12, 2021, and July 30, 2021, respectively. On each surface, 15 divots were created manually by hitting shots with a pitching wedge. The study design included three replications on each surface, with five divots per replication. Additional swings were taken if necessary to ensure each divot had a similar amount of turf removed and underlying soil exposed.

After the divots were taken, they were filled using a divot mix containing 60% sand, 20% peat and 20% soil. The mix used to fill the divots on the bentgrass tee also included chewings fine fescue seed, which is a common practice. Divots in hybrid bermudagrass recover through stolons and rhizomes, so no seed was used in that divot mixture.

To prevent nitrogen applications from influencing recovery time, neither tee surface was fertilized during the study. Irrigation was applied regularly throughout the study to prevent moisture stress. Percent recovery ratings were visually estimated approximately every seven days throughout the duration of each study to determine the differences in divot recovery between both species.

Results

As expected, the two grasses had very different recovery times during this research project (Figure 1). In both studies, the hybrid bermudagrass tee was more than 50% recovered 14 days after divots were created. Conversely, the bentgrass tee took more than 30 days to reach 50% recovery. The percent recovery on the hybrid bermudagrass tee in the first 20 days after divots were taken was greater than the highest percent recovery on the bentgrass tee at any time in either study. After 40 days in both studies, divots on the hybrid bermudagrass tee were more than 95% recovered whereas divots on the bentgrass tee remained less than 80% recovered.

In both studies, the hybrid bermudagrass tee saw the biggest jump in recovery between day seven and 14. After 21 days, divots on the hybrid bermudagrass tee were approximately 80% recovered. In contrast, divots on the bentgrass tee were only 26% recovered in Study 1 and 38% recovered in Study 2 after 21 days. The weather (Figure 2) during the 14 days following the start of Study 2 had more-consistent rainfall, which likely improved bentgrass germination in Study 2 compared to Study 1.

Discussion

This research confirmed our hypothesis that divot recovery would occur faster on a hybrid bermudagrass practice tee compared to a bentgrass tee during the summer months in Pennsylvania. The more aggressive growth of hybrid bermudagrass during summer combined with the presence of belowground rhizomes are likely the primary reasons why we saw faster divot recovery on the hybrid bermudagrass tee compared to the bentgrass tee.

Some superintendents have reported complete divot recovery on a hybrid bermudagrass practice tee after just 10 days, so it might be surprising that the hybrid bermudagrass tee in our research took several weeks to fully recover despite the rapid recovery in the first 20 days.

An interesting observation from this research was that it took more force and sometimes repeated swings to produce a divot of comparable size and depth on the hybrid bermudagrass tee as the bentgrass tee. The dense mat, stolons and rhizomes of the hybrid bermudagrass tee resulted in much smaller and shallower divots compared to the bentgrass tee after one swing. This observation suggests that not only does the hybrid bermudagrass recover faster, it was also more resistant to divoting than the bentgrass. This would likely translate to even faster divot recovery on a hybrid bermudagrass tee during normal play than was observed in this study because golfers would not intentionally deepen their divots as we did for the purposes of divot consistency. A future study could compare recovery time for divots taken with only one swing to see if there was any further difference in recovery time.

We also attribute the lag in recovery to the fact that no fertilizer was applied during either study. Many superintendents apply between 0.5 and 1 pound of water-soluble nitrogen per 1,000 square feet during each month of active turf growth to stimulate growth and recovery on practice tees. The lack of fertilizer applications likely played a role in the recovery rate of both species, but it’s clear that the difference in growth between the two grasses was the driving force behind the differences in divot recovery time.

Is hybrid bermudagrass right for your practice tee?

For golf courses located in areas where both cool-season and warm-season grasses can be grown, planting hybrid bermudagrass on part or all of the practice tee provides an opportunity for rapid recovery during summer when the range is busiest. The downsides to hybrid bermudagrass are the lack of cold tolerance, which can leave turf vulnerable to winter injury, and the dormancy period that starts in fall and may not fully end until midspring.

Of the two major challenges with using hybrid bermudagrass is northern areas, the biggest concern is winter survival. Cold-tolerant hybrid bermudagrasses continue to be planted farther and farther north, but there are limits to where they can be grown without assuming significant risk for turf loss from winter injury. Installing permeable covers has been an effective strategy to protect hybrid bermudagrass practice tees during winter, but the potential for winter injury can never be completely eliminated. If a course has both a cool-season and warm-season grass tee, as Lehigh does, that helps to limit the potential impact of winter injury because the cool-season tee can be relied on for longer into the summer while the bermudagrass recovers.

The second major challenge with hybrid bermudagrass is periods of slow growth or dormancy during colder weather. Divots taken on a dormant or slow-growing hybrid bermudagrass tee won’t recover until active growth resumes, so use is essentially limited to the summer months. Synthetic mats on the back of the practice tee can address this challenge by providing an option for use in the spring and fall when the hybrid bermudagrass tee is not actively growing. Realistically, most courses with any kind of grass practice tee should consider installing synthetic mats for use during periods of slow growth or poor weather, or to allow time for recovery if the tee surface is getting worn out by play.

Another way to overcome the dormancy issue with hybrid bermudagrass is to create a two-tee system, with one tee surface planted with hybrid bermudagrass and another tee surface planted with a cool-season turf. Several courses have had excellent results with this type of practice tee setup, including Lehigh, Philadelphia Cricket Club, Merion Golf Club, Lancaster Country Club, Applebrook Golf Club, Caves Valley and Laurel Creek Country Club. The cool-season tee is used mostly during the spring and fall when the turf can adequately recover from divots. Once the hybrid bermudagrass is actively growing, the cool-season tee is closed to give it time to recover, and then golfers hit off the hybrid bermudagrass tee until its growth starts to slow in the fall. Because hybrid bermudagrass grows so rapidly during summer, it can often handle heavy use even if the tee is undersized.

Another advantage of converting a cool-season tee to hybrid bermudagrass is water savings and reduced costs for pesticide applications, overseeding, divot repair and other labor inputs. Cost savings for some facilities are in excess of $10,000 per year and water use has been reduced by approximately 1,500-3,000 gallons per day during the season.

A potential concern among golfers is that having a warm-season practice tee at a course with cool-season fairways will make the practice experience different from actually playing the course. There are several points to consider on this issue. If a bermudagrass tee allows golfers to play off grass rather than artificial mats more often, most would likely agree that is an improvement. Also, if the cool-season range tee is bumpy and beat up from excessive use, that isn’t really comparable to the fairway experience either. Most players would prefer to have a healthy and dense practice tee even if the strike feels a little different than the fairway grass.

How much will it cost to establish a hybrid bermudagrass tee?

Most courses that have established hybrid bermudagrass practice tees sod the surface so it’s ready for play as soon as possible. The cost of hybrid bermudagrass sod is often around 50 to 60 cents per square foot. This means it’s likely to cost between $21,000 and $27,000 to sod a 1-acre practice tee (not including the cost to remove the existing turf). Permeable covers often cost around 20 cents per square foot ($8,712 per acre), but they typically last for 10 years. This means that the total upfront cost for establishing a one-acre hybrid bermudagrass practice tee is likely to be between $29,000 and $36,000.

Conclusion

Our study supports anecdotal evidence and field observations that suggest faster summer divot recovery on hybrid bermudagrass practice tees when compared to cool-season tees at golf courses in the transition zone and farther north. For instance, courses in New Jersey, Pennsylvania, Ohio, Indiana and Illinois have all had success with practice tees comprised of hybrid bermudagrasses with improved cold tolerance. Hybrid bermudagrass practice tees have their limitations, but they are certainly worth considering in many areas – especially if there is an opportunity to create a two-tee system that utilizes a cool-season and warm-season surface when each is growing and recovering at their best.

Adam Moeller is an agronomist in the Northeast Region and director of Green Section Education.