Bermudagrass can be an excellent playing surface if well maintained. Hybrid bermudagrasses deliver a uniform and dense turf cover that tolerates traffic when actively growing and can survive with less water inputs than most all other turfgrasses. However, maintaining bermudagrass is not without its challenges. One significant issue is that bermudagrass produces stems and aboveground stolons that will grow on top of one another and lay horizontally along the ground. If left uncut, this material will develop a thick thatch-mat that has several negative implications:
- Thatch limits water movement into the soil, which can lead to runoff and localized dry spots.
- A thick thatch-mat produces a more favorable environment for diseases such as Rhizoctonia solani and different spring dead spot pathogens (Ophiosphaerella spp.).
- A thick thatch-mat negatively impacts the playing surface by creating softer conditions, unpredictable bounces and turf may “grab” clubs on shots hit into the grain.
During USGA Course Consulting Service visits with superintendents in Southern California, southern Nevada and southern Arizona, I have seen excellent success using a combination of routine vertical mowing and aggressive scarification methods to stand up and cut bermudagrass stems and aerial stolons. Here are a few strategies to consider this summer to encourage upright bermudagrass growth and reduce grain:
- Conduct light-intensity vertical mowing at least monthly during the growing season. Set vertical mowing blades at about half the mowing height. This light-intensity practice will not disturb aesthetics or the playing surface and won’t frustrate golfers.
- Conduct at least one aggressive scarification event in the middle of summer when bermudagrass will recover rapidly. Courses employing this practice have been successful using a variety of tools such as tractor-mounted vertical mowers and/or metal spring-tine rakes. These implements are followed by mower scalping at a low height of cut – e.g., 0.200-0.250 inch. Other approaches include fraise mowing at various levels of intensity and flail mowing followed by scalping.
- Avoid the urge to fertilize with nitrogen to speed recovery from the aggressive summer scarification process. Additional nitrogen will only encourage more thatch production.
While the aggressive summer scarification process will temporarily disrupt the playing surface, experience has demonstrated benefits such as improved bermudagrass health, reduced grain and a better playing surface. For courses that overseed in the fall, the summer scarification facilitates the overseed process by reducing thatch and encouraging upright turf before the overseed preparations begin.
In summary, plan ahead for an aggressive summer scarification process to remove that bermudagrass toupee and improve turf health and playability.
West Region Agronomists:
Brian Whitlark, senior consulting agronomist – bwhitlark@usga.org
Cory Isom, agronomist – cisom@usga.org