Collars: Winter Injury Update

Picture taken April 26th

After a cold, dry winter, and the second coldest April on record, the hot topic among superintendents in our region has been winter injury in collars.  Talking with quite a few of my colleagues throughout the area, it seems that everyone has needed to replace turf in collars, or is planning on it soon.  As you probably know, we also experienced winter injury on collars.  The first question that comes to mind is: why?  Well, the short answer is that many golf courses in this area, ourselves included, that have Bentgrass greens and Bermuda collars are at risk of the collar encroaching into the green overtime.  As the green gets smaller, the collar "moves" onto the greens mix.  This creates a collar that is on top of the sand greens mix instead of the clay that the original collar was built on.  Sandy soils get much colder and dryer than clay during the winter.  This puts the Bermuda in the collar at a high risk for winter injury relative to the Bermuda that is on the clay in the fairways and surrounds. 


As you can see from the pictures to the right, time and good growing weather have fixed many of the areas that were slow to come out of winter.  There will, however, still be some sod that needs replaced (portions of the collar on #'s 10, 12, and 13 come to mind).

Picture taken May 14th

So, how can we prevent this from happening in the future?  We are currently working with Oklahoma State University to come up with a preventative plan to minimize the risks of winter injury on our collars.  The best way to solve this problem would be to expand the greens to their original dimensions effectively pushing the collars back onto the clay where it is meant to be.  This is a very costly and invasive project and isn't likely to happen in the near future.  Other alternatives are to utilize more cold and drought tolerant Bermuda varieties that can tolerate growing on sandy soils.  This is less expensive yet still cost prohibitive to replace all our collars.  We do plan on planting some different varieties over the next year or so as a trial to see how they perform.  In the short term though, we plan on continuing our cultivation program to improve the health the Bermuda we have, and plan on incorporating amendments into the sandy soil in the collars to help hold more moisture.  Increasing soil moisture is one of the best ways to mitigate winter injury besides using covers, which isn't practical.

Summer is here and great Bermuda growing weather is here to stay, so our collars will only get better and better for the rest of the season.  We appreciate everyone being so understanding while we work through this issue.  As always, if anyone has questions feel free ask.  See you on the course!