We do a lot of work on our putting greens to produce premium playing conditions in South Florida. Bermudagrass produces a lot of thatch, especially ultradwarf bermudagrasses like TifEagle and Champion. Excessive thatch creates poor playing conditions and encourages turf diseases. It is important to apply proper amounts of nitrogen to maintain good turf growth without encouraging excessive thatch on putting greens. However, we also implement regular verticutting, core aeration and sand topdressing on a regular basis to reduce thatch and organic matter.
Putting green collars are the areas directly adjacent to putting surfaces. These areas are generally not maintained as aggressively with verticutting and core aeration, yet they receive the same or more sand topdressing as the putting surfaces each year. In addition to regular topdressing, aeration plugs and debris from cultivation practices are often pushed into the collars resulting in additional sand being deposited. Lastly, mowers pick up sand with the morning dew, and the rollers often deposit sand when mowers turn on the putting green collars. Eventually, the collars become slightly elevated, disrupting golf course playability and turf health.
Grain is another factor that affects playability on putting green collars. Grain is created on most bermudagrass playing surfaces because stems lay in the direction in which they grow. Bermudagrass stems that lie in a particular direction negatively affect playability and overall appearance.
There are several ways to address inconsistent surface elevations and grain. Aggressive core aeration can be implemented to reduce collar elevation, but this practice does not affect grain. Likewise, aggressive verticutting and scalping decreases grain but has no impact on surface smoothness or reducing collar elevation. We implemented a practice at Vanderbilt Country Club that impacts both issues. However, I must warn you that this practice is not for the faint-of-heart and will leave you questioning whether you should have done it. We have successfully implemented this program over the past four summers as we remove our collars every summer with a sod cutter and allow them to grow back naturally.
You must first understand the basic concept of bermudagrass growth to become comfortable with this practice. Bermudagrass produces an abundance of aboveground (stolons) and belowground stems (rhizomes). Excessive stolons create the soft thatch layer and grain that produce undesirable playing conditions. The rhizomes that are present can regenerate a new turf canopy if the stolons are removed. It is important to understand this concept and to have faith that a new turf canopy will indeed develop. This new canopy will be at the same surface elevation as the putting surface and be free of grain. Outlined below are the steps in collar stripping that I have found to be successful at Vanderbilt Country Club over the past few years:
Step 1: Take photos of your green/collar before you start.
Step 2: Mark irrigation heads or drain vents with paint so the sod cutter will not hit them.
Step 3: Start sod cutting around the collar. Set the sod cutter just below the surface (1/4 to 1/2-inch below). The deeper the setting, the longer it will take to recover. The goal is to go just below the surface so that the material cannot be removed as an intact piece of sod, but breaks up and must be removed with rakes. We were conservative the first year and made only one pass around the putting green, but we added an additional pass each year. We are now up to four passes and are comfortable with the process. Set the sod cutter blade at a forward angle and make sure it is sharp. After nine holes, sharpen the blade again.
Step 4: Have a crew with rakes and snow shovels follow the sod cutter and clean-up the debris. By the way, these make perfect sprigs if needed elsewhere on the golf course.
Step 5: Core aerate any additional mounded areas that cannot be smoothed by simply sod cutting and raking.
Step 6: Lightly topdress low areas, if needed, and treat as a grow-in for the next four weeks.
For the first week, you will question your decision and whether you should dust off your resume. However, as long as you keep the collars moist and encourage them with light fertilizer applications, you will begin to see growth by 10 days after collar stripping.Collar stripping with a sod cutter is aggressive, as it removes the entire turf and upper soil layer