Winterkill and Recovery Update

Dr. Kevin W. Frank, Dr. J.M. Vargas, Jr., and Dr. Trey Rogers
Michigan State University

In the last couple weeks the extent of winterkill to Poa annua putting greens throughout mid to southeast Michigan has become evident.  On many greens we have observed several different colors of turf as winter receded and spring slowly arrived.  Generally the Poa annua that retained green color did of course survive and in many locations is now actively growing.  Poa annua that was brownish in color has slowly started to recover and our hope is that most of these areas will fill back in as temperatures and soil temperatures continue to warm.  The Poa that was white or dark gray to black does unfortunately appear to be dead.  Scratching at the turf or taking samples from these areas you may find some and I emphasize some, turf that has survived but to get these areas back in play will require seeding and/or sodding, and limiting traffic.

The different colors of winterkill.

Temporary Greens

One of the most common questions we have answered recently is if temporary greens are necessary.  Damaged putting greens will recover faster if temporary greens are used.  Traffic on Poa annua that is trying to recover or on newly seeded creeping bentgrass will lengthen the time for reestablishment and may even kill the new seedlings.  It is difficult to set a date for when damaged greens can be opened for play as Mother Nature reminded us again with snow and low temps this week that she is still in control.

Winterkill to Tees, Fairways, and Rough

Generally the damage to tees and fairways was not as severe as the damage to putting greens.  However perennial ryegrass, which is often used on driving range tees in Michigan, also suffered winterkill.  The good news with perennial ryegrass is due to its rapid germination and emergence; time for reestablishment should be shorter.     

Perennial ryegrass fairway test plot at HTRC sustained significant damage.

The rough on many golf courses was also damaged from snow mold activity.  Whereas greens, tees, and fairways are typically sprayed with snow mold fungicides to protect the turf, the rough typically not sprayed.  The rough will generally recover from any snow mold damage and in most situations won’t require any reseeding but limiting cart traffic in these areas is advised to allow recovery. 

Rough damaged by snow mold will recover but restricting traffic will help.

Reestablishment

Efforts to reestablish and recover winterkilled turfgrass are already underway on golf courses.  Many damaged greens have already been interseeded with creeping bentgrass and many more will be seeded in the coming days.  Sod from nursery greens on golf courses is also being used to patch small areas of dead turf. 

Surviving Poa annua emerging in verticut channels.

Spreading the Winterkill Message

In the last couple weeks I have conducted several radio interviews discussing winterkill on golf courses with the goal of explaining the issue and preaching patience from golfers.  One of the most recent was for the Greening of the Great Lakes radio segments that will air throughout the state this weekend.  You can listen to the interview by following this link (the audio is near the bottom of the article) http://goo.gl/93psbi