The severity and range of cold-temperature damage across the region is now realized and recovery efforts in most areas are underway. Results from a Northeast Region Green Section survey, field visits, and conversations with golf course superintendents indicate that damage occurred in central and southern New England states, upstate and metropolitan New York, Long Island, New Jersey, and Pennsylvania. Approximately 80 percent of survey respondents indicated their facilities experienced winter injury. Of those reporting winter injury, 75 percent indicated approximately 25 percent of their green surfaces were injured, and 20 percent of respondents estimated greater than 25 percent surface damage. The survey and reports indicate that the damage, though widespread, was largely isolated to water-holding areas. It is no surprise that annual bluegrass and perennial ryegrass were most severely damaged. Following are some common questions Green Section agronomists are hearing and their answers:
1. What caused winter damage this year?
There were several mechanisms associated with this season’s winter injury, which is not unusual. Some golf courses were impacted by weather events in December and January that left dormant turf and frozen surfaces encased in ice. A deep layer of snow and long periods of ice cover created low-oxygen, or anoxic, conditions. Anoxic conditions were identified in central Massachusetts by early February, causing plant condition to slowly deteriorate from suffocation. Some damage may have directly occurred from anoxic conditions. However, anoxic conditions also may have severely weakened plants, leaving them less able to tolerate the cold temperatures and freeze/thaw cycles that occurred in March after the surfaces were exposed.
Damage also occurred later in February when ice formed during even colder temperatures. Although superintendents reported the fermentation smell associated with anoxia, anoxic conditions were probably not in place long enough to cause direct damage to annual bluegrass. Some turf damage may have occurred when ice rapidly formed during flash freeze events. However, it is more likely that damage occurred in March as turf in saturated soils and standing water was exposed to unusually cold temperatures.
Finally, some coastal courses experienced high winds that removed snow cover, leaving turf exposed to record cold temperatures in February and March. The desiccating effect of wind and exposure to very cold temperatures likely damaged turf in those exposed sites.
2. Why was our golf course damaged while other similar courses in the area were not?
This may be the most difficult question of all to answer. There are many variables that impact turf survival during winter, some of which may or may not come into play at a single golf course. Winter damage often varies between sites on the same course and from one course to another. Variables like growing environment, soil conditions, grass species, traffic patterns, maintenance philosophies and other factors all can affect winter injury. Therefore, course comparisons are always difficult, especially when comparing winter injury.
3. Is there anything we could have done differently?
It is always good to evaluate management practices and ask what can be done differently. However, in most cases there is little that can be done to prevent winter injury once annual bluegrass and perennial ryegrass are subjected to ice and very cold temperature. It is always recommended to monitor conditions in the field as closely as possible, especially when ice layers form. Check for the fermentation smell associated with anoxic conditions. Keep track of the number of days turf is under ice. Pull plugs from low-lying areas to see if damage has occurred. Steps can be taken to open drainage paths through snow and slush to encourage surface drainage during periods of winter thaw. Sometimes, ice layers can be removed soon after they form, but removing ice is risky, especially if insulating snow has to be removed to expose the ice layer. Furthermore, removing ice after 40-60 days does not guarantee success.
4. What should we do for the fastest recovery?
The fundamental requirements for rapid recovery are soil warmth and adequate moisture. Use covers and darkening agents in early spring to elevate soil temperatures as much as possible. Covers also will help retain some moisture in the rootzone, benefiting seedlings and existing plants. Furthermore, early season irrigation is important, especially where grass has been injured but not killed. Keep in mind that exposed, weakened plants can desiccate quickly even in cooler spring temperatures. Create a good seedbed with shallow-tine cultivation or slice seeding. One of the best ways to speed recovery is to eliminate traffic from severely damage greens. Foot traffic and seeding do not mix. This is especially true with some of the aggressive shoe patterns that can easily tear and damage young plants. Foot traffic over seeded areas will greatly slow recovery.
5. What can we do to prevent this from reoccurring in the future?
The best long-term advice we can provide is to grow grass species that can tolerate cold temperatures and ice. Converting grass species sounds easier than it is for most facilities; however, creeping bentgrass continues to show the ability to tolerate temperature extremes and long periods of ice cover. Creeping bentgrass is not immune to cold-temperature injury, but it has better chances of surviving winter conditions when compared to annual bluegrass. Creeping bentgrass is not for every facility but should be a strong consideration for those that can provide the proper growing conditions. Kentucky bluegrass also has good cold-temperature tolerance and may be an option where perennial ryegrass is used.
Even if annual bluegrass remains the dominant species, steps should be taken to ensure greens have adequate sun exposure, good surface drainage and dry wells or risers to underlying drains in pockets. Additionally, fall maintenance practices should focus on promoting healthy plants that can more efficiently tolerate cold and ice during winter. Northern sites that are frequently damaged during the winter may be good candidates for winter cover systems. However, even with winter covers, the likelihood of future cold-temperature injury exists as long as annual bluegrass is the primary species.
We hope those with injury have seen damaged areas improve as soils slowly warm. Do not hesitate to contact your Green Section agronomist for help evaluating your situation, developing recovery strategies and analyzing options to best alleviate winter stress.
Source: Jim Skorulski, Agronomist
Contact Dave Oatis, Director
Contact Elliot Dowling, Agronomist
Contact Adam Moeller, Agronomist
Information on the USGA’s Course Consulting Service
Contact the Green Section Staff.