Roundup Weed and Grass Killer Super Concentrate, 1-Gallon Best Roundup brand concentrate value for really widespread weed problems For use in tank sprayers For use around flowers, shrubs and trees; on patios, walkways, driveways, gravel areas and mulch beds; along fences, edging and foundations; as well as large areas such as lawn replacements or garden plot preparation Rainproof in 30 minutes Weeds usually yellow and wilt in 2-4 days