The Pacific Northwest is known for having a climate, with a lack of extreme heat and cold on the west side of the Cascade mountain range. Turf loss on and around putting greens occasionally occurs, but this past summer and fall introduced a pathogen that has been around, but had not caused turf loss – Pythium. Many golf courses (at all budgetary levels) in western Washington and Oregon struggled with turf loss on one or several greens, however recovery with our ever-present Poa annua occurred during the fall. As December arrived, most golf courses reported good recovery with all grasses beginning their normal hardening process as cold nights arrived. However, the month of December had two major cold snaps (single digit to low teens throughout western Oregon and Washington) that have had a significant negative impact on golf greens throughout the area. This is especially true for those golf courses that suffered from Pythium damage in the fall. Golfers need to know what happened - and that your golf course is definitely not the only one that has suffered with green closures and potential turf loss.

Top Left: New additions on greens or new greens with high sand content construction have been affected all over western Oregon and Washington from the hard freeze in December after a mild and wet November. Top Right: High sand content drains have suffered from cold temperature stress. Bottom Left: Traffic on turf that is not covered with frost can still cause turf loss when the green is frozen or thawing. Bottom Right: The first step in determining if severe damage has occurred is to take a core sample into your maintenance facility and observe regrowth.

Every golf course is different and the damage seen on golf courses through TAS visits or via photos varies as to the cause. Desiccation on areas built with high sand content (drain lines, new construction, heavy sand areas near bunkers, accumulated sand on collar edges), crown hydration with excess water in the upper root zone while frozen underneath, and traffic wear around holes that could not be changed are the most common problems viewed. In some cases, the turf loss has increased due to foot traffic on frosted areas, excess shade from nearby trees, excessively low mowing heights, and excess organic material near the surface that caused anaerobic conditions at the surface. Regardless of what caused the weakness of the greens at your golf course, there are a few key programs critical at this time to assure the best results possible entering the spring growing season.

1. Take a core sample of the weakened area. Remove the core and place it near a window at your maintenance facility. Observe if the core begins to recover after a few days. If it does, count your blessings as the crowns of your plants are still in full functioning operation. If not, service the sod cutter or be prepared for either fast recovery with sod or slower germination and coverage with Poa annua or bentgrass seed.
2. Raise your mowing heights. For years USGA agronomists have been recommending (some would say harping!) on not going too low with mowing heights as the potential for stress-related disaster is increased. This would be a classic example of this type of natural disaster for those that do not raise mowing heights during the fall and winter months. With handicaps being frozen from November through February in the Pacific Northwest, it has never made sense to not raise mowing heights to improve turf survival during potentially difficult winter conditions.
3. Keep players off recovering surfaces. The decision to have temporary greens or simply remove play from the greens during these types of conditions is a step in the right direction. This is especially true after damage has occurred, thus removal of harmful foot traffic is needed now if your greens are showing the signs of winter damage.
4. Let ‘em breathe. The extended weather forecast for the remainder of this winter into the spring is warmer and drier than normal due to a strong El Nino. If this occurs, opening up the surfaces with small, solid aeration tines or spiking when the surfaces are dry will help in the recovery process. This is most important for any areas that suffered from traffic wear or that display anaerobic conditions near the surface. Also, move hole locations to green edges to avoid normal desirable hole locations that will be used when growth resumes.
5. Remove trees if they are part of the problem. Damage this winter is generally related to tree shade, however many greens have been viewed that simply have no trees on the south side. Regardless, if trees are on the south or east side of your greens it is always best to provide more sunlight to create stronger turf growth prior to and during the winter months.

Warmer weather will be coming that will improve recovery of Poa annua greens all over western Washington and Oregon. In the meantime, golfers must understand that their golf course is not alone as public, municipal, private, and resort courses have all reported damage to one or more greens. Nature is one up, but there are still a lot of holes to play!

Source: Larry Gilhuly, lgilhuly@usga.org