News Release

For Immediate Release: April 13, 2001

The potential for winter kill in the New England region is higher than ever before. Now that the snow and ice have finally melted, golf course superintendents are trying to evaluate the damage and assess the long-term effects that this past winter will have on the golf season.

The USGA Green Section, the nation's chief authority on turfgrass management, has been tracking this problem and released an updated report as well as an informative Q&A on the outlook for New England courses.

Northeast News Update
By: Dave Oatis, Director, and Jim Skorulski and Jim Baird
USGA Agronomists
The word around much of central New England and eastern New York is not good as the snow pack recedes and temperatures warm. Superintendents in the Boston region, western Massachusetts, Vermont, and western Connecticut report varying degrees of winter damage to annual bluegrass on greens. Shaded turf, areas of poor surface drainage, and areas where ice/snow damming occurred have suffered the worst damage. The same type of damage will likely become evident on annual bluegrass fairways as well once the snow has disappeared.

A few surviving bentgrass plants in a predominantly dead, Poa annua turf.

The first indication of trouble became obvious in mid February and early March when superintendents broke through heavy snow and ice layers and detected a foul smelling, anaerobic condition. Anaerobic conditions are never a good omen and signal the need to take action. Efforts were made to remove snow in order to expose the ice layer and hasten melting. Darkening agents or fertilizers were applied, and some superintendents physically removed ice. Unfortunately, in many cases, the damage had already occurred, and annual bluegrass and perennial ryegrass, (the two species most prone to this type of winter injury) suffered extensive injury.

Golfers will ask plenty of questions as they learn of the damage and likely-hood of playing temporary greens. We will try to answer some of those most-likely asked questions.

Q. What caused the injury?
A straightforward question that, unfortunately, does not have an easy answer. The damage observed in the field is limited primarily to annual bluegrass and perennial ryegrass most likely caused by a form of cold temperature injury, better known as crown hydration injury.

The damage is related to the ice, and probably occurred during one of the weather events where warmer temperatures were followed by an abrupt temperature drop and ice formation. The process is complex, but it involves water freezing in open spaces around individual plant cells in the crown portion (growing point) of the plant. The ice crystals forming around the plant cell pull water out of the cell causing dehydration inside the cell. The process causes irreversible damage to cell membranes and death to the individual cells. A hardened plant can tolerate this condition, but once a plant loses hardiness (a natural occurrence in late winter) individual cells lose the ability to combat the dehydration process and severe injury can occur. The process is still not fully understood.

Q. Did the ice and heavy snow pack suffocate the turf?
The anaerobic or anoxic condition under the ice would lead one to this conclusion, but it is unlikely. Scientists have shown that annual bluegrass can tolerate a solid ice layer for 40 to 60 days without harm. However, the toxic cyanide, hydrogen sulfide, and carbon dioxide gases trapped below the ice can lower a plant's cold temperature hardiness leaving it more susceptible to the injury described above. The gases may be a result of plant respiration and decomposition of damaged plant tissue. Therefore, it is our feeling that steps should be taken if possible to remove impermeable layers of ice once the anaerobic condition is detected and or the ice has been place on annual bluegrass at or about 60 days. Creeping bentgrass can tolerate ice cover for 100 days.

Q. Should the snow and ice have been removed earlier in the winter?
This is a loaded question, but it is our feeling that it is generally not a good idea to do so; especially in the colder interior parts of the region where low air temperatures can become lethal. A layer of snow provides excellent insulation to the turf and can prevent some of the freeze/thaw cycles that are responsible for the loss of cold temperature hardiness and the damage itself.

Q. Would geotextile covers on our greens have prevented this type of damage?
Absolutely not! Perforated covers alone would have had no effect on the type of winter injury that occurred this season since they provide little or no insulation and do not prevent hydration of the plant. The covers are helpful for preventing desiccation from wind and will be useful in hastening the recovery. There are more extensive covering systems being used further north with good success, and some promising new covering materials are making their way into management programs to combat this problem.

Q. What effect does shade have on winter injury?
Annual bluegrass populations are always higher in shaded areas, and since that grass species is most susceptible to cold temperature injury, it is likely that damage in those areas will be most severe. The shade reduces a plant's photosynthetic ability and thus limits its cold temperature hardiness in late fall. Thus a shaded plant will always be more susceptible to this type of injury as compared to a plant growing in full sun.

Q. What can we do to prevent this from reoccurring in the future?
Steps can be taken to reduce the chance of injury from cold temperature and ice, but it probably will never be prevented entirely if you have large populations of annual bluegrass. Correcting poor surface drainage, eliminating shaded environments, and establishing more tolerant creeping bentgrass will help reduce the extent of the injury. Proper cultural practices to allow the turf to gain maximum cold temperature hardiness, the use of new covering systems, and snow and ice removal programs all can help reduce the injury as well. However, it should be noted that there are no guarantees.

Q. How long will the recovery process take?
The rate of recovery will depend upon the weather and temperatures this spring. Damaged greens, particularly where the damage is located in the primary cupping areas, should be closed and temporary greens used until the turf has regained density. Playing on the damaged greens during the recovery slows recovery and prolongs the duration of surface disruption. Moving to temporary greens, however distasteful it may seem, is your best means to initiate a rapid and successful recovery effort.

Recovery Programs

The recovery process requires several basic steps.

1. Evaluate the extent of the damage
2. Determine a plan of action to complete the recovery
3. Communicate the plan with the Green Committee or Owner
4. Procure the necessary materials for the plan

Communication is critical throughout the recovery process. Golfers need to understand the need to play temporary greens, your decision to choose seed or sod, the use of covers, the starting date for the recovery program, the added labor anticipated for the recovery work, the anticipated date of recovery, etc. Use digital images or pictures to illustrate the extent of the damage that has occurred to help prepare golfers and avoid surprises. Images also are helpful in highlighting your efforts in removing snow and ice and in reestablishing turf.

When should you start?

It is true that bentgrass seed will not germinate until the soil temperatures reach 50° F. Initiating efforts before that point is questioned by some, however initiating recovery work early (when soils are workable) will make sure seed is in place should warm weather arrive early. The cultivation work also may help the soils warm more quickly. Finally, clear plastic 4mm covers can be installed over the surface to artificially elevate soil temperatures and obtain earlier germination. The clear plastic material should be removed once the seed germinates. Geotextile covers can be applied at that point to try to maintain higher soil temperatures and avoid desiccation.

Seed can be pregerminated to get an early jump when soils are cool. Several pregermination systems have been developed for this purpose, and information concerning those systems is available through our offices. Primed bentgrass seed may also become available from local suppliers. It too can reduce time periods for seed germination in cold soils.

In conclusion
Winter damage is not that unusual in the Northeast. Regrettably, damage occurs somewhere in the region just about every year, and for some, it is the single biggest challenge we face in this part of the country. Winter injury is never easy to accept and the recovery can be painfully slow in a cold spring. Please feel free to contact our offices if you have any questions concerning the winter injury or while developing a recovery program.

©2004 Massachusetts Golf Association.