Mixing two or more herbicides can dramatically increase the spectrum of weed control. Most mixtures have a wide safety margin on desirable grasses and some are specially formulated for sensitive grasses such as bentgrass. Mixtures generally are available in amine salt and low-volatile ester formulations. Ester formulations are the materials of choice in early spring, late fall, and during rainy weather. Amine salt formulations generally are safer than esters around nontarget plants and during period of warm weather.