So granular forms of an herbicide are safer for use in landscape plantings, but may not provide as good control as sprayable forms. Oxyfluorfen and oxadiazon are preemergence herbicides that provide weed control through contact activity. They form a chemical barrier on the soil surface and burn off weed seedlings that grow through it. Applied in the granular form, they are very safe on a wide range of ornamental plants. If applied to the same range of plants in the sprayable form they can severely injure or kill them.
Some herbicides are available in both amine and ester formulations.
The amine form is water soluble, while the ester form is oil based and is available as an emulsifiable concentrate. The ester form provides somewhat better weed control when applied to their foliage, but it is much more volatile. This means it should not be applied in hot weather because of the risk of volatilization and drift onto nearby crop plants. The term active ingredient refers to the amount of actual chemical in the formulation. Oxadiazon is a chemical name.