From the Golf Course Superintendent
I recently attended the Carolinas Golf Course Superintendent's conference in Myrtle Beach. As you can imagine, the "big buzz" is all about the new Ultradwarf bermudagrass varieties for greens. I attended two seminars dealing with the installation process and maintenance needed to provide optimum putting conditions on a year-round basis.
I first learned that the maintenance expenses between growing bermudagrass vs. bentgrass for putting greens is a wash. This is different from the original propaganda out there a few years earlier. There are less fungicides applied to bermudagrasses, but the aggressive verticutting and topdressing combined with winter covering, more than equal out expenses between the two. Verticutting reduces grain while the sand topdressing dilutes the thatch that is produced by the aggressive growth habit of the new Ultradwarfs. Verticutting and topdressing is done weekly from June through August to maintain an optimum-putting surface. Equipment maintenance is increased due to the abrasion of the sand as it passes through the reel. The greens are double cut daily during periods of excessive growth and rolling is a must. Cutting heights are near .125 of an inch in the summer and rise to .22 of an inch by October. The height-of-cut is raised in slight increments dictated by soil temperature as dormancy approaches. During this period the speeds will be the most inconsistent as decisions to adjust cutting heights will coincide with the fluctuations in temperatures. Once dormant, the greens are painted to provide an aesthetically pleasing appearance.
There are three main varieties of Ultradwarfs being used. There is one that has been more popular in our area, but courses that can afford any variety they want have also used the other two. If this is something we do in the future, we are fortunate that all will have been put to the test through several different seasonal variations and used at clubs with varying budgets. Again, play these courses in all seasons and make your own judgment concerning if the ball roll is what you prefer to the bentgrass that we now have.
A major concern will be green speeds. I feel the green speeds can be controlled, for the most part, through proper agronomic practices. With the undulations on a few of our greens, it would be best to keep speeds between 10 and 11 inches on the stimpmeter. The only time this would be hard to control would be during the winter months when greens are frozen and dormant. The greens would be covered and unplayable if temperatures drop below 25 degrees and do not rise above 40 degrees the following day. This is the advice of the university research, but many lower budget clubs do not even own covers. This is playing a bit of "Russian Roulette" as you will not know the outcome of your decisions made regarding covering until spring of the following year. If turf were lost, sodding or sprigging would have to be done to re-establish during June and July.
Shade is the biggest concern in successfully maintaining the Ultradwarfs. Bermudagrass needs 8 – 10 hours of sunlight, with the most important being between the hours of 11 am and 3 pm. Not all shade is created equal. Shade from clouds is spectrum neutral and has a minimal impact on plant growth, while shade from trees is not and changes the ratio of blue light to red light, which can affect plant growth. Using a light sensor and meter prior to tree removal, would allow us to isolate and remove only the guilty culprits. Sunlight angles vary by 36% throughout the year, so assessments taken in each season would be most valuable. The best scenario for optimum growth would be no shade produced by trees.
I hope this article will help you understand that even with all the hype that is out there, being educated on the facts concerning the maintenance and growth characteristics of the new Ultradwarf bermudagrasses is needed to make any decision on a future conversion successful.
Richard McDanel, CGCS