Some weed species, such as dandelions, are a problem you can count on seeing every spring. In contrast, many courses have good years and bad years dealing with crabgrass or goosegrass based on the weather. Unfortunately, foxtail is an annual grassy weed that has been particularly troublesome in tall grass roughs throughout the Central Region this season. Left unchecked, foxtail can transform wispy turf into an unsightly, unplayable jungle.
The solution to foxtail is simple enough but a challenge to implement. A well-timed application of pre-emergence herbicide during spring can provide season-long control of foxtail and other annual grassy weeds. However, many turf managers experience inconsistent levels of weed control in tall grass roughs because they fail to prepare them for pre-emergence herbicide applications.
A critical step in the process is to scalp down tall grass roughs and remove excess plant debris before making herbicide treatments. Pre-emergence herbicides need to contact soil to be effective, and a thick mat of dead grass creates a dense barrier between a sprayer and soil. As an added bonus, the practice of scalping down the turf provides some control of certain weeds on its own.
Many courses use flail mowers to scalp down tall grass roughs during late fall, remove the debris from flail mowing and then mow again with rotary units at a lower height of cut during early spring. The additional mowing operation improves the chances that pre-emergence herbicide applications will reach the soil. In addition, the tire tracks left by application equipment will be less visible during summer if applications are made to short, freshly mowed turf rather than tall stands of grass. Spray volume can also be increased to help pre-emergence herbicides penetrate turf canopies and reach the soil.
Some courses with extensive acreages of tall grass roughs use farm implements to scalp roughs and harvest debris as described in the USGA article, “Makin’ Hay.” Prepping tall grass areas for pre-emergence herbicide applications by mowing and collecting debris is a laborious, time-consuming operation, but it is well worth the effort if you prefer clean roughs over weed patches.
Central Region Agronomists:
Bob Vavrek, regional director – bvavrek@usga.org
John Daniels, agronomist – jdaniels@usga.org
Zach Nicoludis, agronomist – znicoludis@usga.org
Information on the USGA’s Course Consulting Service
