One of the biggest challenges wherever bermudagrass and other warm-season grasses, like zoysiagrass and seashore paspalum, are grown, especially in turf areas maintained above putting green height, is common bermudagrass. Some courses have such pressure from common bermudagrass that it becomes the primary grass throughout the course and is managed as such.
Common bermudagrass is widely considered to be the turf world’s worst weed. Spraying it with glyphosate alone will not kill it. It is also extremely problematic to maintain as a golf course playing surface. It can require double or triple the rate of trinexapac-ethyl, a growth regulator, needed to produce improved playability compared to other types of bermudagrass. Common bermudagrass has great genetic variability, and its behavior and growth is dictated by both vegetative and reproductive priorities. In other words, it wants to produce seed and spread. Unlike hybrid bermudagrass varieties that are sterile and vegetative in growth only, it is difficult to coerce common bermudagrass into producing the year-long surface characteristics golfers desire. During winter months – even in areas that don’t experience freezing temperatures – common bermudagrass areas are the first to exhibit signs of wear, lose their leaves and canopy, and lose color. Common bermudagrass will also lag behind other grasses in regrowth or recovery from stress and thinning. When the spring arrives, off-color, worn-out common bermudagrass that is often just stems devoid of leaves often will flush out with seedheads. Seedheads are not conducive to play and, even with daily mowing, they continue to develop – often at the expense of vegetative canopy.
For these reasons and others, common bermudagrass is typically not a desirable grass for golf courses. There are some ways to minimize its expansion once it becomes established, but there is no surefire way to selectively eliminate it from desirable stands of zoysiagrass, seashore paspalum and bermudagrass. Most golf courses try their best to mask its presence so that golfers are less likely to notice or have their lie impacted.
The best prevention against common bermudagrass is to keep it from ever becoming established, and if it does occur to quickly remove it and re-sod with the assistance of nonselective herbicides. Keeping your preferred grasses healthy and dense will reduce the risk of common bermudagrass gaining a foothold. For example, common bermudagrass often pops up in areas of warm-season turfgrass where large patch leads to thinning of the desired turf.
Common bermudagrass is a common problem and a common complaint at many golf courses I visit. Most complaints coincide with when peak rounds occur, like during the winter in Florida and the warmer coastal areas, or during the spring and early fall in more temperate areas. There are ways to minimize its expansion and even potentially reclaim areas when common bermudagrass contamination starts, but this takes time and labor that may not fit the budgetary constraints of the golf course. Developing and communicating a plan before trying to address common bermudagrass issues is critical for success, don’t hesitate to contact your regional USGA agronomist for help. The gain in coverage of your preferred grass is not without pain when deciding to go after this common problem.
Southeast Region Agronomists:
Chris Hartwiger, director, USGA Course Consulting Service – chartwiger@usga.org
Steve Kammerer, Ph.D., senior consulting agronomist – skammerer@usga.org