If you decide to use one of these products, read the label carefully. Often, a crop oil must be added to the spray solution for the herbicide to work well. Some grassy weeds are not controlled such as bromegrass and sandbur. Mature tall fescue also is not controlled though seedling tall fescue is. Established bermudagrass is knocked back but rarely killed.
Though both these products can be used over the top of numerous broadleaf plants (including iris), there are some differences in labeling. For example, if you need to control grasses in vegetables, choose Poast as Fusilade is not labeled for vegetables. However, Poast products cannot be used on all vegetables and the waiting period between spraying and harvest may be so long as to make use impractical. To see a label for one of the products that contain sethoxydim, see Hi-Yield Grass Killer. (Ward Upham)