It contains two active ingredients: Bromacil, which controls weeds through root contact and gives season-long residual control, and 2-4-D which controls weeds through foliage and gives immediate weed burn down. The degree of weed control and duration of effect will vary with the amount of product used, soil type, rainfall and other conditions. Apply any time of year except when the ground is frozen. Best results are obtained after predominant species are well established in late spring or early summer.