It’s difficult to find many negative side effects associated with the unusually mild weather we have experienced throughout the upper Midwest this season. Turf disease pressure has been light; with little more than an occasional outbreak of Microdochium patch during the cool weather or dollar spot when it warms up a bit.

However, low soil temperature equates to slow turf growth, and slowly growing turf will have difficulty competing with weeds, especially sites that were killed or thinned by winterkill. As a result, there has been no shortage of weeds such as crabgrass and clover in the short grass and milkweed, thistle, and Queen Anne’s lace in the naturalized, unmowed roughs.

Many courses are converting more acres of mowed rough into natural turf areas to help reduce maintenance costs. Golfers are usually willing to accept and sometimes embrace the presence of well placed natural roughs, but they quickly lose patience with these sites when they become overrun with unsightly weeds.

It’s nearly impossible to do little more than remove weeds by hand or make spot applications of herbicides to weeds in tall grass roughs during August. Many weeds can be taller than the spray boom by mid-summer and sprayer tracks through the natural roughs will be an eyesore for the rest of the season.

One option for consideration is to map the heaviest and/or most visible infestations of weeds and target these areas for an application of pre-emergence herbicide later this fall. Several courses visited recently had achieved excellent control of weeds in natural areas where the tall roughs were scalped down during late October or November and then treated with Gallery herbicide just before winter. Excess plant debris needs to be removed before spraying to ensure as much soil contact as possible. The difference between treated and untreated roughs with respect to weed encroachment was dramatic and the effects persist well into the season. An ounce of prevention can definitely be worth a pound of cure for high priority roughs that have developed a consistent history or weed encroachment.

Source: Bob Vavrek, rvavrek@usga.org or 262-797-8743