Controlling Florida betony (Stachys floridana) with herbicides.
In the southeastern United States, Florida betony continues to be a problem weed in both turfgrass and ornamentals. Several herbicides including atrazine, dichlobenil, and glyphosate can provide good control (greater than 70%) of Florida betony, but their uses are limited. Over the past several years, many additional herbicides have been added to the turf market. New herbicides evaluated in this study included the sulfonylurea herbicides foramsulfuron, metsulfuron, and trifloxysulfuron; the picolinic acids clopyralid and fluroxypyr; and the aryl triazinone herbicide carfentrazone in combination with 2,4-D, dicamba, and mecoprop. In both the 2004 and 2005 trials, all sulfonylurea herbicides provided greater than 83% control of Florida betony at 10 wk after treatment. Other herbicides that provided less than 80% control of Florida betony in 2004 and 2005 included clopyralid, fluroxypyr, and the carfentrazone combination treatment. Selective control of Florida betony in ornamentals, however, still remains a challenge, as none of these herbicides are labeled for ornamentals.