Crown Hydration and Winterkill

Let's talk about the current state of some of the greens here at BVGC. Some of the greens here experienced various areas of winterkill (more specifically crown hydration injury) over the late winter. Crown hydration is a situation where an extremely wet and snowy winter (especially late) combined with frequent warm-ups and re-freezing causes turf injury. The grass plants begin to take up water as the winter ends and the snow melts, but if cold temps and refreezing occurs the water will form ice crystals inside the plant and rupture it (i.e. blow it up from the inside). Annual Bluegrass (Poa annua) is especially susceptible to crown hydration injury.  Making things worse is the fact that shade enhances the problem: 1)more shade generally means more Poa and therefore a more susceptible grass species 2)more shade means slower snow melt and therefore more likely to have crown hydration injury due to refreezing.  

On to the factors that are specific to the greens and the crown hydration injury here at BVGC...First, we need to revisit the weather that was specific to Woodstock, not Ohare and not some lakeside Northshore club.  Reports of winterkill are numerous in central and southern Wisconsin.  The winter came late but came with a fury.  We received nearly 2" of rain on the last two days of January, followed by a rapid freeze.  This caused a layer of 6-8" of ice to accumulate on the green surfaces.  Prolonged ice cover can itself damage the turf, but it slows the melt process and enhances crown hydration injury.  From February 1 through late March we had several large snowfall events until things started to thaw towards the end of March.  I knew the prolonged ice and snow cover was going to be a concern and the staff on hand attempted to remove snow from several greens in mid-March to try to speed up the melt process.  It may have helped but ultimately damage has occurred on many greens here.  

Trying to remove the snow from 13

Thick thick ice cover with 6" snow on top

The greens that are in full sun have minimal amounts of Poa and the snow melted off more rapidly helping to minimize the damage but even they show signs of damaged Poa.  The greens that bore the brunt of the damage are 5 and 13, and to a lesser extent 6, the right side of 8, the collar on 16 and the front of 14.  13 and 5 share common characteristics such as high Poa populations, intense shade and saddle-shaped greens that inhibit surface run-off.  Greens such as 6,8 and 14 have these same issues, just not on the same scale as 13 and 5 which is why the damage is much less.  

In terms of recovery and re-establishment we have done a litany of agronomic procedures including: Slit seeding 4x with Creeping Bentgrass seed to speed recovery and try to establish a more desirable species, increased nutrients, the purchase and use of greens covers as seeding blankets to warm the soil for faster germination and multiple aerifications.  

Late March, just after snowmelt.  Grooves are from Slit-seeding

1st of April

29th of April just before aerification

May 17th

Even though it may not look like it, I am actually pleased with the re-growth.  April was abnormally cold and wet which is a difficult combination to re-establish turf.  If a more "normal" April had been around, I would have expected 13 and 5 to be where they are today a few weeks ago but the cool weather delayed recovery.  This is why we closed the holes until May 3rd as they were not as far along as we would have liked.  If they were anything but par 3's with water we could have cut a temporary cup but alas the beauty of those holes also limits our options at times.  At this point we will continue to "baby" 13 and 5 with additional nutrients, a higher height of cut to promote recovery and additional needle tine aerifications and overseedings.  

Believe me, we as the Ground Staff of BVGC are doing everything in our power to return the course to its normal summer conditions.  I know there have been complaints and I sympathize.  The frustrating part is the selective short memories of a hand-full of members: 1) Reports from long time members and staff verify winterkill has occurred on 13 at least twice before 2)The same dedicated staff that worked countless hours to ensure BVGC survived the heat and drought of 2012 were boxed into a corner by uncontrollable weather at a time of the year where very little could be done 3) Anyone who watched the Wells Fargo Championship at the Quail Hollow Club outside of Charlotte, NC should appreciate the fact that despite the involvement of some of the brightest minds in turf management, huge budgets and countless resources a golf course that had been know for having some of the best greens on the PGA tour had issues with  several greens at tournament time because Mother Nature decided to throw them a series of curveballs over the past 2 years.  

The past two weeks has been much more conducive to re-establishment of the damaged areas and hopefully a nice "normal" summer awaits.  Please be patient as every effort is being implemented to restore the damaged areas but this will be ongoing.  Pins may be located in similar spots away from the thin spots so you may see a hole playing the same more frequently than before.  Please comment and/or contact the golf shop for more details.

For more information regarding crown hydration please visit:
http://turf.msu.edu/winterkill-of-turfgrass

For USGA Agronomist Bob Vavrek's report about freeze/thaw in the upper midwest please visit:  http://www.usga.org/course_care/regional_updates/regional_reports/northcentral/A-Notable-Exception---February-2013/

Thank you for your patience,
Eric Radkowsky